March 2021 – TumbleStone

Little Wing Boutique, Riverton: Gemstone Beach Polished TumbleStones For Sale

Little Wing Boutique Shop, 130 Palmerston Street, Riverton.

Gemstone Beach at the car park.

Gemstone Beach further west.

Some Gemstone Beach stones, just out of the tumble polisher.

One of the photo-books for sale.

In August 2020, at the end of a fossick on Gemstone Beach with my sister Helen, I met a woman who was there with her dog and a friend. She was interested in the fact that I was collecting stones. She and I were both members of the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. I showed her a few of the stones I had gathered and a few polished ones I had in my pocket. I gave her a nice pendant-shaped green hydrogrossular garnet. Her name was Kat, she lived in Riverton, and one of the things she did in her busy life was run a small vintage recycled shop on the main street. As I was starting the drive north back to Whanganui a few days later, it crossed my mind that maybe Kat might be interested in stocking some of my Gemstone Beach polished stones for sale. She responded positively and on 31 August I posted just over 200 stones to her, along with copies of two of my photo-books. (See here for an introduction to Gemstone Beach.)

I also sent Kat four information pamphlets on different types of stones to give customers a bit of background and context about them. First of all, there were what I simply called “Gemstone Beach Stones”, “tumble-polished naturally-occurring stones from Gemstone Beach…Each stone is unique but carries within it a significant part of New Zealand’s geological history”.

Pamphlet on Gemstone Beach stones in general.

Some Gemstone Beach stones, just out of the tumble polisher.

More Gemstone Beach stones, just out of the tumble polisher.

Another selection of Gemstone Beach stones, just out of the tumble polisher.

I also sent Kat a number of hydrogrossular garnet stones, a type of stone that draws many people to Gemstone Beach.

Pamphlet on hydrogrossular garnet stones.

Hydrogrossular garnet from Gemstone Beach.

Hydrogrossular garnets from Gemstone Beach.

Hydrogrossular garnet from Gemstone Beach.

Another type of TumbleStone from Gemstone Beach which I sent to Kat was banded ignimbrite, a volcanic stone.

Pamphlet on banded ignimbrite stones.

Banded ignimbrite stone from Gemstone Beach.

Banded ignimbrite stones from Gemstone Beach.

Finally, I sent a few trace fossil stones too, argillite with the 250 million year old marks of small burrowing animals.

Pamphlet on trace fossil stones.

Three trace fossil stones from Gemstone Beach.

Trace fossil stone from Gemstone Beach.

Kat’s shop is Little Wing Recycled Boutique, located at 130 Palmerston Street in Riverton, right next to the town’s only ATM. Formerly called Remix Boutique, its Facebook page is still under that name. The shop’s description is as follows: “Preloved women’s clothing & accessories. Locally made jewelry & more. Vintage & retro fashion & other quirky items.” Opening hours are 11 am to 4 pm every Wednesday and Thursday and 11 am to 3 pm on Sundays. Among the recycling dresses and shoes and old vinyl records and vintage jewelry are now some dishes of polished TumbleStones from Gemstone Beach. I took the following photos when I visited in November 2020:

Little Wing Boutique Shop, 130 Palmerston Street, Riverton.

Inside Little Wing Boutique.

Gemstone Beach TumbleStones for sale.

One of the photo-books for sale.

Gemstone Beach TumbleStones.

Some of the stones sold in January this year and I took some replacements to Kat when I was in Riverton in March.

Some of the stones that have been sold.

“Replacement” stones are in the glass container at back.

March 2021.

I am grateful to Kat for stocking these stones. She welcomes everyone to her shop anytime, if only for a browse and a chat!

Another South Island Fossicking Trip, February/ March 2021 – Last Two Days (Leithfield Beach, Kaikoura Coast, Ward Beach)

The first Post in this Series is here.

Day 23, Thursday 11 March – Leithfield Beach and Kaikoura Coast. I spent nearly three hours on Leithfield Beach this morning on a cloudy day threatening rain, but the rain moved across to the north of me.

I always walk southwards from where I park the car at Leithfield Beach to fossick around these old stormwater pipes. The person near them provides scale.

Looking out to sea over the old stormwater pipes.

Leithfield Beach stones this morning, looking north. There is rain in the distance which fortunately did not come my way.

Leithfield Beach stones.

Probably a spotted shag.

Here are seven jaspers found on Leithfield Beach – I especially like the yellow in them. The seven go from the most to the least yellow, the least red to the most red. These stones are often less smooth than the ones I collect at Gemstone Beach and Kakanui, reflecting the state of most stones on the beach.

And another four stones from this morning:

Small stone. likely to have a lot of chaceldony (agate) in it.

It has been suggested that this is rhyolite.

Very unusual circular pattern on this stone.

I also found an unusual sea-weed like stuff on the beach and posted photos of it on the “New Zealand Lapidary, Rocks, Minerals, Fossils” Facebook Group (see first two photos below).

Found on Leithfield Beach.

Among the stones on Leithfield Beach.

Found on Leithfield Beach.

Stan Wen, a Group member, did some research on it and eventually identified it as the strobila of a certain kind of jellyfish, part of its asexual reproductive process, as illustrated in this diagram from the Seattle Aquarium.

jellyfish33

The Aquarium information states: “When a [jellyfish] polyp strobilates—segmenting its body to reproduce—it releases tiny ephyra into the water. Within a few weeks, a bell appears and the ephyra are considered medusa [adults].”

I then drove to Kaikoura and, in the late afternoon, spent about 40 minutes on the beach near my motel. Here are six stones from that fossick, the first of which has dendrites in it. A dendrite forms when a mineral, starting from a point of origin in the stone, migrates and branches outward.

The beach near my motel, looking back towards the Kaikoura Peninsula.

Kaikoura beach stones, late afternoon.

Dendrites in a stone.

Limestone. Likely to be too soft to polish.

Limestone. Likely to be too soft to polish.

Day 24, Friday 12 March, Last Day – Kaikoura Coast and Ward Beach. I often stop at a little spot on the Kaikoura Coast between Kekerengu and the Waima/Ure River mouth. I am especially interested in the stones there with zoophycos trace fossils. As noted on page 64 of “A Photographic Guide to Fossils in NZ” by H. Campbell et al. (2013), these trace fossils can be found in Muzzle Group geological strata in Marlborough, in fine-grained limestone, marl, mudstone and siltstone, laid down in deep water (over 150 metres), the traces due to burrowing activity by something like an echinoderm (see first photo below for this extract). The stones in the photos below are examples of the range of types of traces I found today, both at my Kaikoura Coast spot and at Ward Beach just over 20 kilometres north. These stones are likely to be too soft to tumble polish well so I left many of them on the beach.

Page 64 of “A Photographic Guide to Fossils of New Zealand” by Hamish Campbell et al. (2013).

Zoophycos trace fossil. The nested curving chevron-shaped trace is one I find particularly attractive.

Another zoophycos trace fossil from the Kaikoura coast.

Stone from Ward Beach.

Parallel zoophycos.

Another Ward Beach zoophycos.

Intersecting trace fossils.

Less organised and less well-defined, but traces probably as well.

A Ward Beach stone with a variety of zoophycos trace fossils.

Ward Beach stone, where the zoophycos traces are harder than the surrounding stone material so are slightly raised.

Some more photos from my stop on the Kaikoura Coast between Kekerengu and the Waima/Ure River mouth:

The beach between Kekerengu and the Waima/Ure River mouth. Looking south.

The stones on the beach. The white limestone(?) stones stand out.

Gorgeous green stone, maybe quartzite?

This stone looks like one where the burrowing that produced the zoophycos traces ended up producing actual holes in the stone (or the burrows were petrified with softer material and eroded away). Or maybe the burrows were made by a different animal. The other side of this stone is equally interesting (see next photo).

The other side of the previous stone.

About 12 kilometres further north on State Highway 1 is the small village of Ward. Ward Beach is about six kilometres off the main road, to the east, set among spectacular scenery – high hills with steep slopes and a coastline with interesting rock formations. The Ward Beach boulders (concretions) are not far from the car park (maybe 10 minutes walk north), although I did not visit them today. The beach was uplifted by the 2016 Kaikoura earthquake, unveiling the boulders.

The Ward Beach boulders – photo taken during an earlier visit.

Ward Beach boulder.

When I arrived, there were about 6 to 8 people from the WSP company (formerly Opus), a Design, Engineering and Environmental Services Consultancy, picking up rubbish as a community service. One of them showed me a mannikin leg he had found, and I gave him a florescent light tube I had found. For a sense of the beach and its setting, see this web page.

Scenes from Ward Beach today:

Looking towards the Ward Beach car park.

Ward Beach stones.

Ward beach in front of the carpark, lowish tide.

White-faced heron on Ward Beach.

A surfer in high seas, just in front of the car park.

Five of the stones I found today on Ward Beach:

Gorgeous little stone I found at Ward Beach. Could be a quartzite.

Other side of previous stone.

Treasure

My trip back over Cook Strait the next day was uneventful in stark comparison to the sailing of nearly four weeks previously!

Another South Island Fossicking Trip, February/ March 2021 – Days 21 and 22 (Kakanui, Temuka)

See here for the first Post in this Series.

Day 21, Tuesday 9 March – Kakanui. On my last day at Kakanui, I spent four hours on the beach between 10.30 am and 2.30 pm, then later another hour between 6 pm and 7 pm. Great weather and great fossicking!

A couple of oyster catchers moving away from me on the Kakanui beach.

The south end of the beach.

Just past the rocks shown in the previous two photos is this small cove which is often piled high with stones. Can be accessed at low tide or otherwise by climbing over the rocks.

Three sea gulls over the Kakanui beach.

Today’s selection of finds are presented in the order I found them. And I will reverse my usual presentation for each stone – first will come the close-up image then the image of the stone itself. Most of these stones should by now be familiar to those who have read previous Posts in this Series – jasper, quartzite, agate. Here are the first six:

Quartzite?

Like caramel.

Jasper.

Fossil hash stone. One side.

Fossil hash stone. Other side.

Another five finds:

Treasure

Could be a type of fossil hash.

Quartzite?

Dark red jasper?

One side of a small beach agate.

Other side of small beach agate.

And a final five Kakanui finds:

Another fossil hash stone.

Another jasper.

Another beach agate.

Small banded jasper.

Quartzite?

Day 22, Wednesday 10 March – Travel day, driving from Kakanui to Amberley, no beach visits partly due to heavy rain. But I called in on Penny Farmer (and Francis) at Temuka in response to her invitation delivered through the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. Penny showed me her stone cutting saws and tumblers and the many interesting rocks and pebbles she has accumulated in her shed and garden. She tends to collect much larger specimens than I do, and one of her fossicking areas is Kakanui. She gifted me a few stones, including these two unpolished cut slices and small jasper (many thanks! and thanks to Francis for an excellent cup of coffee!). The close-up photos of these stones have been “brightened” a little to show more detail (partly because the images were taken in dull conditions).

One of Penny Farmer’s cut slices that she kindly gave to me. Probably jasper.

Another of Penny Farmer’s cut slices that she kindly gave to me.. Again, probably jasper.

A grit-tumbled jasper stone given to me by Penny Farmer.

The last Post in this Series, on Days 23 and 24, is here.

Another South Island Fossicking Trip, February/ March 2021 – Days 19 and 20 (Kakanui, Moeraki Village, Katiki)

See here for the first Post in this Series.

Day 19, Sunday 7 March – Travel day. I drove north from Riverton to Kakanui (near Oamaru), and made a brief reconnaissance visit to Kakanui Beach (planning to spend two days here). I arrived at my favourite Kakanui Beach late afternoon and spent about 30 minutes checking out what stones were around. Here are five that I found:

This reasonably plain whitish quartz stone has this on its side.

Treasure

Limonite prase, a kind of jasper. This one has less holes than most.

Probably stained quartz.

Light coloured quartzite.

Plain beach agate, not a bad size.

Day 20, Monday 8 March – Kakanui, Moeraki Village and Katiki. To start off with today, I spent 3 1/2 hours on the beach near Kakanui.

The stones on the beach near Kakanui this morning.

You can see the wet strip of stones I followed today while fossicking. Looking south.

Looking northwards, towards Oamaru.

I went as far as these rocks, which are about 800 metres along the beach.

I found quite a few of the yellow and red quartzites that I like. I first came across a type of yellow quartzite at Birdlings Flat, near Christchurch, a few years ago and was pleased to discover even more of them appearing in the Kakanui area. Some have some red in them, and some I thought have almost no yellow (or red) at all. Here are 11 of these stones found today, starting with predominantly red ones, moving through to yellow ones then to increasingly plainer ones. Yet all the same type of quartzite, I reckon.

Among the other Kakanui stones I found today were these seven:

Fossil hash stone.

Not sure what might have caused these two flower-like-shapes, either fossils or some mineral process.

And these seven:

Nice sized quartzite.

Treasure

Small quartzite.

Jasper.

Another jasper.

In the afternoon I tracked back south for about 30 kilometres to visit a small beach not far from Moeraki village, a recommendation from Oliver who had earlier introduced me to Slope Point.

One end of the small beach near Moeraki Village.

Looking towards the other end of the beach.

Seagull on the small Moeraki Village beach.

There were seals at both ends of the beach so I did not venture further.

Oliver said I might find some agate there. And I did – botryoidal agate, seam agate, and sea-tumbled beach agate.

Botryoidal agate.

Seam agate, wet.

Beach agate, wet.

Other side of beach agate.

As noted by Jocelyn Thornton on page 11 of “Gemstones”, this form of cryptocrystalline silica is more accurately called “chalcedony”, with “agate” being used for the banded variety (see also Te Ara: The Encyclopedia of New Zealand). The Quartz Page provides a well-considered view on this. However, in New Zealand most varieties of chalcedony are often simply called agate. (Malcolm Luxton in “Agates of New Zealand” refers to some types of non-banded chalcedony as agate, such as those with mineral inclusions.)

Chalcedony is composed of very fine intergrowths of quartz and moganite. It is microcrystalline meaning the crystals are microscopic and cannot be observed by the naked eye. Both quartz and moganite have the same chemical formula SiO2 (silicon dioxide) but different crystal structures. When free from impurities, chalcedony is colourless and transparent. Dependent on impurities introduced during its formation, chalcedony comes in a wide variety of colours including red, yellow, green, blue, purple, grey, and white.

I was astounded to find the piece of botryoidal chalcedony/agate, having never come across it before. It was partly buried in the sand and I missed it first time I walked past. I went back a few paces for some reason to look at something else and noticed it from that direction.

One of the other sides of the botryoidal chalcedony.

Another side of the botryoidal chalcedony.

Held up to the sun.

As one website puts it, “Botryoidal minerals form when many nearby nuclei, specks of sand, dust, or other particles, are present. Acicular or fibrous crystals grow radially around the nuclei at the same rate, appearing as spheres. Eventually, these spheres abut or overlap with those that are nearby.” The Moeraki/Kakanui area is well known to have agate/chalcedony, as indicated on the map of rock collecting sites in Te Ara (see photo on left below). The Otago Rock and Mineral Club have a photo of a botryoidal chalcedony with a movable cap from the Moeraki area and a piece from Moeraki sold last year from the Trevor Gray collection (photos centre and right below).

Source: https://teara.govt.nz/en/map/5113/rock-collecting-sites-in-new-zealand

Source: https://sites.google.com/site/theotagorockandmineralclub/photos-of-nz-rocks-minerals-and-fossils-1

Moeraki area botryoidal chalcedony. Source: https://www.facebook.com/TheFamilyJewelsDunedin/posts/154609632961753

Seam chalcedony or agate is a form of this type of rock where layers build up to fill cracks and cavities in sediments (instead of occurring in holes left by gas bubbles in volcanic rocks). Jocelyn Thornton’s “Gemstones” includes an example on page 11. Craig McGregor has an interest in a particular type of seam agate found on the beaches on the south side of the Moeraki Peninsula. He calls it “Tobacco Agate” because of its very streaky layering. Again, I was astounded to find a good-sized piece of seam agate high up the beach, with very few other stones around it.

“Top” of seam chalcedony, dry.

Seam chalcedony held up to sun.

“Bottom” of seam chalcedony, dry.

“Top” of seam chalcedony, dry.

“Side” of seam chalcedony, wet.

The sea-tumbled beach chalcedony/agate I found might have started off as a seam but through wave action, being rolled against sand and other stones, it became shaped into a rounder form. You can often see tiny “concussion” marks on the surface of beach chalcedony, caused by being slammed into rocks and stones by waves and/or the current. Such marks are most noticeable when the stone is dry.

The beach-tumbled chalcedony I found, dry.

Concussion marks.

After my visit to this small beach near Moeraki Village, I went south another few kilometres to the Katiki Beach North Reserve Rest Stop. I had noticed some stones on the beach there yesterday when driving past. A scattering of stones was to be seen across pa lot of the beach. A 20 minutes fossick turned up a handful of interesting stones, and the potential existed for more, but the afternoon was wearing on and I headed back north to Kakanui and my accommodation.

Katiki Beach, looking north.

Katiki Beach, looking south.

The scatter of stones on Katiki Beach.

Stones on Katiki Beach.

Katiki beach stone.

Katiki beach stone.

Katiki beach stone.

The next Post in this Series, on Days 21 and 22, is here.

UP-DATE OF “The Seven Stages in Tumble Polishing Stones” – One Less Stage

The stones used in the seven stages series.

100 grit.

Identifying holes during the process of tumbling.

The soap tumble after 200 grit tumble.

A polish tumble.

A Series of Posts called “The Seven Stages in Tumble Polishing Stones” was begun in November 2017. It went through, step-by-step, the seven stages of how I polish stones using a tumbler and 4lb barrel. A set of 40 beach stones collected from Riverton were used to illustrate each stage. The first Post in the Series is here, while a summary can be found as #2 in “Six Past TumbleStone Posts of Interest to Beginning Tumble Polishers”. However, changes in the grits and polish supplied by the Rotorua Lapidary Rock and Mineral Store in late 2020 mean that now only six stages are required instead of seven, and a couple of other minor changes have occurred.

About six months ago, Rotorua Lapidary changed the silicon carbide grit and tin oxide polish that they stock. Before that, they stocked 100, 220 and 320 grit along with pre-polish and pro-polish tin oxide powder. Now, however, the store stocks 80/100, 220 and 400 silicon carbide grit and only one grade of tin oxide recommended for tumble polishing (called “Tumble Polish”). So there are three main changes. First, the coarse grit size 100 grit has been replaced by 80/100, which means the latter contains a slightly wider size range, the overall effect being that it is slightly coarser. To all intents and purposes, this is not a significant change (though it will make the price lower). The second main change is that 320 grit has been replaced with a finer 400 grit. I asked Rotorua Lapidary by email why this change was made and they replied: We have a new supplier and they don’t stock 320 grit, 400 grit is finer therefore beneficial when working towards the polishing process. The third main change is that two grades of tin oxide polish powder have been replaced with one polish powder. In response to my inquiry about this change, Rotorua Lapidary stated: The new supplier has a one step polishing product which we trialled very successfully, and have every confidence in supplying the market... The tumble polish is still the same type of polish as the pre and pro polish only it is slightly finer in micron – with using 400 grit (which is finer) instead of 320 grit you can eliminate the pre polish process. So the main effects of the second and third changes are to reduce the number of stages required by one, along with a small reduction in the overall costs.

The new 400 grit from Rotorua Lapidary.

The new Tumble Polish tin oxide powder from Rotorua Lapidary.

My original seven stages in tumble polished stones were: Stage One = Stone collection (not usually included in accounts of tumble polishing). Stage Two = About a week in 100 mesh silicon carbide grit followed by a soap wash for a few hours. Stage Three = One week in 220 mesh silicon carbide grit followed by a soap wash. Stage Four = 320 silicon carbide grit followed by a soap wash. Stage Five = Tumbling in a tin oxide “Pre-Polish” powder (five microns in size) for three to five days, followed again by a few hours soap tumble. Stage Six = The “Pro-Polish” tumble, using tin oxide powder of one micron size, for at least one week. Stage Seven = A “burnishing” tumble for a week in borax.

My up-dated stages are now reduced to six, as follows: Stage One = Stone collection. Stage Two = About a week in 80/100 mesh silicon carbide grit followed by a soap wash for a few hours. Stage Three = One week in 220 mesh silicon carbide grit followed by a soap wash. Stage Four = 400 silicon carbide grit followed by a soap wash. Stage Five = Tumbling in “tumble polish” powder for at least one week. Stage Six = A “burnishing” tumble for between two and seven days in borax. See the Summary Table below.

Summary Table

STAGE	ORIGINAL SEVEN	UP-DATED SIX
ONE	Stone Collection	Stone Collection
TWO	100 grit, 7+ days	80/100 grit, 7+ days
THREE	220 grit, 7+ days	220 grit, 7+ days
FOUR	320 grit, 7+ days	400 grit, 7+ days
FIVE	Pre-polish, 3-5 days	Tumble Polish, 7+ days
SIX	Pro-polish, 7+ days	Burnishing, 2-7 days
SEVEN	Burnishing, 7 days

Table Notes: a) Tumbles in soap follow each stage (except the last). b) “7+ days” means “7 days or longer”. c) I now sometimes do a shorter final burnishing stage depending on how bright the polished stones are.

Currently I am using 400 grit for tumble polishing (as I ran out of 320 grit) but as I still have some stocks of pre-polish and pro-polish powder I have not yet moved to the six-stage process.

Note that different people have developed different stages for tumble polishing which use different grit sizes etc. What is common to them all is the use of a coarse grit first (provided it is needed – smooth beach stones can be started with a finer grit), followed by a medium-to-fine grit, then a pre-polish stage using very fine grit or a pre-polish powder, then finally the polish stage. See, for example, the Gold Rush Trading Post’s stages and those of Mama’s Minerals.

UP-DATE OF “What Do I Need to Start Tumble Polishing Stones Myself? And What Will It Cost Me?” Changing Prices, New Grits and Polish

The two-part Post “What Do I Need to Start Tumble Polishing Stones Myself? And What Will It Cost Me?” was originally done by me three years ago in April 2018. However, prices have changed since then, as have the grades of grits and polish that are stocked by my supplier. The Covid-19 pandemic has also disrupted international trade and shipping. So I updated the original Post, setting out the main changes in light green. The edited Post is here.

My supplier is the Rotorua Lapidary Rock and Mineral Supplies Ltd. I bought my first tumbler and grit etc. from them and find that they provide excellent service and very fast dispatch. Other people have supported this view. If their website shows they are out of something, it’s worth contacting them by phone or email as they may simply not have listed it yet or need to re-package it from bulk supplies.

About six months ago, Rotorua Lapidary changed the silicon carbide grit and tin oxide polish that they stock. Before that, they stocked 100, 220 and 320 grit along with pre-polish and pro-polish tin oxide. All my Posts about my own tumble polishing on this Blog reflected the use of these five “stages”. Now, however, Rotorua Lapidary stock 80/100, 220 and 400 silicon carbide grit and only one grade of tin oxide recommended for tumble polishing called “Tumble Polish” (they also have a very expensive “Pure Tin Oxide”). In response to my inquiries in November 2020 about these changes, Colin Simmons advised me:

We have a new supplier and they don’t stock 320 grit, 400 grit is finer therefore beneficial when working towards the polishing process. The new supplier has a one step polishing product which we trialled very successfully, and have every confidence in supplying the market… The tumble polish is still the same type of polish as the pre and pro polish only it is slightly finer in micron – with using 400 grit (which is finer) instead of 320 grit you can eliminate the pre polish process.

I still have stocks of everything except 320 grit so I am now using the 400 grit instead. I am still using both pre and pro-polish and will probably do so until they run out. I may try skipping the pre-polish as an experiment, but have yet to do so.

Note: You may wonder about the difference between “80/100” and “100” silicon carbide grit. As Rocktumbler.com notes, the grit size relates to the size of the particles of grit, with grit size 80 being 250 microns, size 100 being 149 microns, size 220 being 68 microns, size 325 being 44 microns, size 400 being 37 microns and size 600 being 20 microns. A “micron” is 1/1,000,000th of a meter, or 1/1000th of a millimeter. So a particle of 60 grit being 250 microns across is about 250/1000th or 1/4 millimeter across. Ungraded grits, or grits within a grade range, do not require the same level of processing needed for specifically graded grits. That allows such grits to be sold for a lower price than graded grits. Silicon carbide sold as “80/100″grit would have a range of particle sizes smaller than 80 grit (250 microns) but larger than 100 grit (149 microns).

Another South Island Fossicking Trip, February/ March 2021 – Days 17 and 18 (Gemstone Beach, Tsunami Alert)

See here for the first Post in this Series.

Day 17, Friday 5 March – Gemstone Beach. I had planned today to spend a few hours on Gemstone Beach. However, the North Island of New Zealand experienced a 7.1 magnitude earthquake at 2.27 am this morning off East Cape, waking many people. A tsunami alert was issued, but then later lifted. At 6.41 am, a 7.4 magnitude earthquake struck near the Kermadec Islands, 1,000 kilometres north-east of the country, followed by an 8.1 magnitude shake two hours later. Due to this new and increased tsunami risk, parts of the North Island coast were evacuated and the rest of New Zealand came under a beach and marine threat advisory that “strong and unusual currents and unpredictable surges near the shore are expected”. (See a newspaper article about this here.)

Even though Gemstone Beach was at the furthest point on the country’s southern coast from the tsunami threat, I decided not to proceed with my fossicking plans. All the alerts and advisories were eventually lifted in the afternoon, although people who ventured onto beaches were told to remain alert and cautious. In the late afternoon, I decided to make a short visit to Gemstone Beach (I spent 50 minutes there) where I kept well away from the waves and fossicked in and near the Taunoa Stream mouth, just 200 metres from the carpark.

The circled area was my fossicking area today. (The tide was further out than this when I was there.) Source: Google Maps.

Stones in the Taunoa Stream.

Stones in the Taunoa Stream.

I bought a booklet called “Orepuki and Surrounds Heritage Trail” from the Riverton Museum (“Te Hikoi”) shop which refers to the naming of Taunoa Stream. John Boultbee was an English sailor who arrived at nearby Pahia in 1826 and lived with the Maori there for a year. “In his journal, Boultbee noted a ‘small kainga Toonau’ (Taunoa). This village/kainga was situated near the mouth of the Taunoa Stream, one kilometre west of Orepuki. Twenty years after Boultbee had written about this village, there was nothing left of the site as the Taunoa Stream had become the sludge channel into which all the [gold] miners dumped their tailings” (page 11).

Here are six of the stones I found during my short visit to the mouth of the Taunoa Stream:

Today’s trace fossil stone, a small one with nicely defined traces.

One of the bigger stones I collected today.

Intriguing!

Other side of previous stone.

Small stone, with raised colourful segments.

This one was even smaller, but fascinating…

Small purple stone.

Previous stone from the top.

Very nice complex stone.

Day 18, Saturday 6 March – Last visit to Gemstone Beach. I managed to spend nearly 6 hours on the beach today, finally tearing myself away at 4 pm. The unsettled sea yesterday and overnight had stirred up the stones a bit, as I found some really interesting ones.

Looking across a bit of a wild sea at Gemstone Beach to the mountains of Eastern Fiordland.

Gemstone Beach further west.

Gemstone Beach waves.

Spot the pink stone…

The pink stone!

Gemstone Beach at the car park.

I decided today to show first of all a photo of a stone which gives some idea of its size in my hand, with the second image then being a cropped version of the first photo to show close-up details of the stone. As a result, the first photo may include glimpses of my gumboot and/or my camera wrist-strap. Here are six of today’s finds:

Unusual light colour, interesting inclusions.

Lots of greys.

Stunning small stone.

Very small stone…

Banded argillite, with some fault lines.

Small but vibrant.

Another eight:

Very small quartz stone.

Trace fossil stone,

Maybe because of the recently unsettled seas, I found more hydrogrossular garnets today than usual. This is the stone most sought after on Gemstone Beach. It is also the fourth of the 13 minerals first identified in New Zealand, having been identified in 1943. Here are six of the stones I found today that probably have hydrogrossular garnet in them:

Stone with hydrogrossular garnet in it.

Small white hydrogrossular garnet.

Slight green tint to this hydrogrossular garnet.

Nice brown hydrogrossular garnet.

The next Post in this Series deals with Days 19 and 20, on the start of my journey back north.

Another South Island Fossicking Trip, February/ March 2021 – Days 15 and 16 (Slope Point, Gemstone Beach)

The first Post in this Series is here.

Day 15, Wednesday 3 March – Slope Point. NOTE – OCTOBER 2023 – Landowners are now refusing access to this beach, so please do not visit there without permission. I spent four hours on a beach near Slope Point today, at low tide. Slope Point is the southernmost bit of land of the South Island, 70 kilometres east of Invercargill. The sea and wind can be ferocious here but today was very calm. I had visited the Point in 2018 but it is located high atop cliffs and I couldn’t see how to get down to any beach.

Slope Point is the southernmost part of the South Island. Source: Google Maps.

A photo taken when I visited Slope Point in 2018.

Slope Point itself is atop high cliffs with large waves pounding at it.

The small beach to the west of Slope Point that I visited with Oliver.

There is a useful page (p.35) on Slope Point in Jocelyn Thornton’s “Gemstones”. It is an area known for rhyolites and petrified wood and other volcanic pebbles and petrified material. Rhyolite is a volcanic rock with a high silica content (obsidian, pumice and ignimbrite are are common varieties of rhyolite). There is a photo of tumble-polished Slope Point rhyolites on Craig McGegor’s website. In 2019, I met Jack Geerlings on Gemstone Beach – he is a long-time rock hound and polisher from Winton. He invited me to visit him to view his collection. He had a number of polished rhyolite stones from Slope Point there.

Jack Geerling’s display of Slope Point rhyolite.

Jack Geerling’s collection.

Part of Jack Geerling’s display of Slope Point rhyolite.

Another part of Jack Geerling’s display of Slope Point rhyolite.

Access to a beach in the Slope Point area is not straightforward but it is well worth the efforts to get down to a beach. Many thanks to Oliver Simpson, contacted through the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils” for a very companionable time and for sharing his knowledge.

Looking at the northeast end of the small beach near Slope Point.

Looking back at where we had to drive to, over a couple of paddocks.

The stones on this Slope Point beach.

In behind the beach is a small lagoon with petrified wood in it.

Petrified wood in the small lagoon.

I found a few interesting stones, some of which were rhyolites, others maybe petrified wood or other material, along with some other kinds of stones like jasper and quartz.

Not sure what kind of stone this is – it could contain small fossils.

Probably rhyolite.

Jasper, I think.

I don’t know what this stone is. It was found by Oliver who generously gave it to me when I admired it.

Probably rhyolite.

Probably rhyolite.

Also probably rhyolite.

Petrified wood:

A hunk of petrified wood on the beach, about 15 cms across.

There are pieces of petrified wood in the rocks – this piece is about 4 cms long.

A lot of the petrified wood here is very dark, common in Southland.

Small piece of petrified wood.

Even smaller piece of petrified wood.

Two of Oliver’s pieces of petrified wood, each about 10-12 cms wide.

Finally, a few more Slope Point beach pebbles:

A type of quartz pebble.

Some kind of fossilised forest floor or??

Maybe a jasper?

Slope Point breccia.

Day 16, Thursday 4 March – 8th visit to Gemstone Beach. I spent four hours here today, around low tide. It was a cooler day, with a stiff wind, 12 degrees to start with. By the end of the four hours, it was sunny, my backpack was heavy, and it was 17 degrees.

Low tide at Gemstone Beach this morning.

Gemstone Beach stones.

This bank of stones is about 4 to 5 metres high.

Gemstone Beach stones.

Here’s six of my interesting finds:

Very unusual construction.

Gorgeous jasper.

Quartz.

Quartzite.

The mauve colour in this stone caught my attention. Probably mineral-stained quartz.

Interesting stone texture.

Another five interesting finds:

The ligh-coloured material is a higher surface than the dark.

Fine veins and pastel colours.

One of the hydrogrossular garnets I found today.

This type of stone can be found from time to time on the southern coast.

After my visit to Slope Point yesterday, I became more aware of rhyolite on Gemstone Beach.

Many stones on the beach are gorgeous but not all can be tumble polished, so I leave them behind. Some are too big or too pitted or too soft. Some examples from today of the “too big” type:

Quartz. Too big to tumble – left on the beach.

Also just a big too big.

Banded argillite. Left on beach as too big for my tumblers.

I wonder if the white material might be agate?? Or quartz?? Close-up next photo. Left on the beach because too big.

Quartz, too big.

Breccia with shell fossil, too big.

The next Post in this Series, for Days 17 and 18, reports on visits to Gemstone Beach but in contrasting circumstances, during a national tsunami alert.

Another South Island Fossicking Trip, February/ March 2021 – Days 13 and 14 (Gemstone Beach, The Beach Past the Back Beach at Riverton)

The first Post in this Series is here.

Day 13, Monday 1 March – 7th visit to Gemstone Beach. This visit lasted 4 1/2 hours, the sky was cloudy but the temperature was warm, and there was little wind. Today’s top four finds:

Not sure whether this might be fossil coral or not.

Other side of previous stone.

Probably banded argillite.

Other side of previous stone.

Another of those purple stones, with interesting inclusions.

Outstanding detail.

I think this is a quartzite. A small stone.

I went onto the beach this morning when the tide was low but starting to come in. Decided to walk westwards further than I normally do. However after two hours I decided to turn back as the waves were starting to get high on the beach. I made it back to the car park just in time. The waves were lapping the cliffs in places, and it wasn’t even fully high tide. Much care needs to be taken at Gemstone Beach as the waves are powerful and the banks of stones can be steep, and the cliffs are right at the back of much of the beach.

Gemstone Beach early on in my visit.

Later, Gemstone Beach with high powerful waves sprinting up the banks of stones. The beach near the car park is more benign though care is always required.

Here are five more of today’s finds:

Today’s “pinkie”.

Banded ignimbrite.

Quite a small stone.

I don’t know what this is.

Probably iron-stained quartz of some sort.

Day 14, Tuesday 2 March – The Beach Past the Back Beach, Riverton – I spent just over an hour at this beach this morning, at low tide, the best time to get around the rocks. (Two years ago I did a Post on some stones from this beach which included a location map.) I walked over a hill to get there, then once on the beach walked back towards the Back Beach, eventually prevented from getting right back to it by high rocks, stopping only 100 to 150 metres from the Back Beach.

The western half of the Beach Past the Back Beach. Tihaka Beach and Colac Bay are a few kilometres further on. Most of this morning’s fossicking was behind me, to the east, amongst the rocks there.

Looking back over the hill I had just come over to get to this beach. The Back Beach is on the other side of the hill.

Stones on the Beach Past the Back Beach.

The start of the rocks at the eastern end of the sweep of the Beach Past the Back Beach.

This was as far as I could go this morning. The small cove that is part of the Back Beach is just around the first large rock on the left.

Lots of patches of stones among the rocks. At high tide, this is under about a metre of water.

Lots of stones can be found in these nooks and crannies. See next photo.

This rock is about 5 to 6 metres high.

There are lots of stones on the Beach Past the Back Beach, many similar to Gemstone Beach but not usually of the same bright colours.

Quartzite, probably.

A different coloured quartzite.

This is a small white hydrogrossular garnet. Not usually found this far east along the coast. I have been told of the rare one turning up here, and have found a couple of lower-quality ones in the past two years.

A thulite stone but not as pink as the ones I have found on Gemstone Beach and at McCracken’s Rest. The pink is due to manganese.

Trace fossil stones (argillite) can be found here (and on other Riverton beaches).

An interesting stone due to its band.

An interesting green.

A complex construction.

Interesting hue of blue.

Returning over the hill to my car, I saw a surfer at the Back Beach and took some photos of him. Looking at one of the photos later, I realised there was a dolphin out there as well. On the way back to where I was staying, I passed a spot where I had seen a foiling wind surfer two days previously. Driving past Henderson’s Bay, a stand up paddle boarder could be seen. Later at the crib at Taramea Bay, a man flew a kite in the stiff wind.

Circled in this photo of the Back Beach surfer is a dolphin.

The dolphin.

The surfer, having caught a wave.

The Henderson’s Bay stand up paddle boarder.

A foiling wind surfer near the Back Beach.

Soneone flying a kite at Taramea Bay, Riverton.

The next Post in this Series can be found here, including a trip to Slope Point.

Another South Island Fossicking Trip, February/ March 2021 – Days 11 and 12 (McCracken’s Rest, Gemstone Beach)

The first Post in this Series is here.

Day 11, Saturday 27 February – This afternoon I spent four hours on the Te Waewae Bay beach, accessed from the lookout at McCracken’s Rest, a small off-road parking area eight kilometres west of Gemstone Beach (Orepuki). The coastline of Te Waewae Bay is 27 kilometres long, with Gemstone Beach near the eastern end.

Te Waewae Bay on Foveaux Strait. Source: Google Maps.

Sign post at McCracken’s Rest.

The red pointer is Grindstone Creek – I walked from McCracken’s Rest to about 400 metres past the Creek’s outlet on the beach. Source: Google Maps.

Pointer is at Grindstone Creek. I walked to the point marked by the black cross (lower right). Source: Google Maps.

Part of an Information Panel at McCracken’s Rest.

There are a number of excellent information panels at McCracken’s Rest.

From McCracken’s Rest I walked east for about two kilometres. The beach is largely a continuation of Gemstone Beach, with many of the stones similar. However, there is a little less diversity and a few more bigger stones. The key to a successful fossick on the beach at McCracken’s Rest is timing – most of the stones are high up the beach and in order to see them wet, you need to be there close to high tide. I recommend the period from about 30 to 60 minutes before high tide through to two hours after. Furthermore, take care! The waves are powerful. This is not a swimming beach. Don’t get caught by a wave. Note: Beach access is difficult at McCracken’s Rest, you have to climb over a fence and go down a steep slope.

Looking back up at the McCracken’s Rest lookout from the beach.

Looking east. Gemstone Beach is right in the left distance, 7 kms away. In the distance (centre) is Pahia Hill.

Looking west, towards the Fiordland mountains.

The waves are powerful – you need to be very careful not to get caught by one.

Stones get kicked up by the waves as they hit the beach.

As the tide gets lower, the stones (left) become dry and dull-looking. The lower part of the beach consists of tiny stones.

Grindstone Creek. I turned around about 400 metres past here.

I collected a range of interesting stones east of McCracken’s Rest. Here are four of the smaller ones:

I also found some more pink thulite stones, both small and large:

A large pink stone – it’s about 15 cms in length. I left it on the beach, far too big for me to tumble polish and too heavy to add to my backpack.

Close-up of large pink stone.

Very small pink stone.

Close-up of very small pink stone.

The big and the small.

A dry pink stone – quite big but as I found it near the end of my walk, I decided to keep it. Next photo is of the same stone wet.

The previous stone, but wet. Very pink. Thulite, with the pink caused by the presence of manganese.

Close-up of previous stone.

A few more stones collected from the beach near McCracken’s Rest:

I found a slightly smaller bright purple stone like this yesterday. This one is even better.

Volcanic? Often these stones are chipped or a fragment has fallen out. This stone is is excellent condition.

I am always attracted to stones with veins like this.

The flash of red caught my eye. My backpack was heavy at this stage and I decided to leave this one on the beach.

Nicely shaped trace fossil stone, unusual colour.

Day 12, Sunday 28 February – Gemstone Beach visit again. Arrived at high tide this afternoon and spent three hours on the beach. Weather was partly cloudy and warm. The waves were lapping the cliffs when I got there so I spent the first 40 minutes on the beach in front of the car park and near the Taunoa Stream.

High tide. Standing a couple of hundred metres west of the carpark, looking at where the Taunoa Stream crosses the beach.

The same part of the beach three hours after high tide.

There were a few other people on the beach. I spoke for a while with a couple from Manapouri who were very interested in the stones on the beach, and another couple from Tauranga who were fossicking for hydrogrossular garnets. I found some more gorgeous stones today, some of them in or near the Taunoa Stream. Here are the two outstanding finds of the day: