Category: Slope Point

January 2022, Stone of the Day #10 – Light-Coloured Petrified Wood from Slope Point

Most of the petrified wood in the area of Slope Point, Southland, is dark coloured if not black. Occasionally I have come across a brown piece incorporating veins of some kind of silicate, maybe quartz or chalcedony (agate). This is maybe my favourite Slope Point stone so far (though it might also be one that Oliver Simpson found and gave to me):

This stone is 3.5 cms at its longest. It came out of the polishing barrel yesterday. I had earlier twice given it a 400 grit tumble as it has a number of cracks in it. I didn’t start with 220 grit as I wanted to have some control over its shaping, to make sure I didn’t make it too small while trying to minimise the size of the cracks. It was impossible to get rid of the cracks, but the stone is gorgeous.

The other side of Stone #10.
One of the ends of Stone #10.
One of the edges of Stone #10.

It spent 13 days in tin oxide tumble polish followed by three days in borax.

The following photos include examples of the more common black petrified wood from Slope Point. The first photo is of five stones tumbled in the same batch as Stone #10:

Five polished black petrified wood stones from Slope Point.
Polished black petrified wood stone from Slope Point.
Unpolished black petrified wood from Slope Point.
Unpolished black petrified wood from Slope Point.
The fossicking beaches at Slope Point are to the west of the tourist sign.
Slope Point beach stones.

More TumbleStone Blog photos of polished Slope Point stones, including black and brown petrified wood, can be found here.

Stone of the Day #11 is here. The Index to the January 2022 Stone of the Day Series is here.

January 2022, Stone of the Day #7 – Another Volcanic Stone from a Slope Point Beach

I found this small dark-coloured stone on a Slope Point beach in Southland sometime in 2021 – I didn’t take a photo of it at the time as it was much less interesting than many of the Slope Point stones I collect.

However, some faint marks and lines hinted at possibilities, and these have been brought out well by polishing. It was tumbled with a number of other Slope Point stones (including Stone #3), initially in 400 grit for just over a week, then spent 10 days in tin oxide pro-polish, and four days in borax as a final burnish. It finished the tumble-polishing process at the end of August in 2021.

There are lots of little interesting areas in Stone #6, no doubt related to its volcanic origins. They include the occasional isolated tiny square or oblong (cubic?) crystals that can be seen in the photos above and below.

Some research on the internet has brought up pictures of stones with pyrite crystals that look very similar (e.g. geology.com):

Pyrite crystals. Source: https://geology.com/minerals/pyrite.shtml
Pyrite crystals. Source: https://www.sandatlas.org/pyrite/

Stone #7 is probably rhyolite. It is 4 cms long and rounded, so that a third side can be photographed, revealing further intriguing details:

Stone of the Day #8 is here. The Index to the January 2022 Stone of the Day Series is here.

January 2022, Stone of the Day #3 – A Volcanic Stone from a Slope Point Beach

#3
#2
#1
#4
#5

This stone was found by Oliver Simpson on the first fossicking trip he took me on to a Slope Point beach early in March 2021. He gave it to me in a sudden fit of generosity when I said “Wow!”, and I intend to return it to him now that it has been polished. This is the view of one side of the polished stone:

#3

It is 4.5 cms long and just under 3 cms wide and deep. It has polished better than I thought, with only three or four tiny holes interrupting its shiny surface. It was tumbled first in 400 grit for just over a week, then spent 10 days in tin oxide pro-polish, and four days in borax as a final burnish. It finished the tumble-polishing process at the end of August in 2021.

What amazed me when I was first shown it by Oliver were all the small “inclusions”, which are either crystals (formed during the cooling of the rock) or amygdales (minerals deposited later in small holes in the rock).

A second side of Stone #3.
A third side of Stone #3.

Slope Point is only about 10 kilometres along the coast from the more widely-known Curio Bay, a rock platform where tourists go to gain a close-up view of a fallen petrified forest from Jurassic times. According to Wikipedia, these petrified logs “were buried by ancient volcanic mud flows and gradually replaced by silica to produce the fossils now exposed by the sea”. The remnant of this fossil forest stretches from Curio Bay to Slope Point. It is that ancient volcanic activity that produced many of the wonderful stones to be found on the Slope Point beaches, especially the black petrified wood, rhyolites and fossil tree ferns (see here for examples). When tumbling these stones, a distinctive dark oily slurry is produced, quite unlike the slurry from the other South Island stones I work with.

The account of my first visit to a Slope Point beach can be found in the entry of “Day 15 Wednesday 3 March” here. It also includes photos of this stone on the day it was found. This is the beach that features in the month of November in my 2022 Calendar. All the details of the stone were apparent when it was found – the polishing process has slightly clarified them and kept the stone shiny.

Stone of the Day #4 is here. The Index to the January 2022 Stone of the Day Series is here.

TumbleStone Calendar 2022 – The Beaches, Part Two

2022 Calendar Cover
November’s photos and dates
Leithfield Beach, August
Kai Iwi Beach, September
Gemstone Beach, October

The 2022 TumbleStone Calendar is titled “Fossicking Beaches”, featuring mainly South Island beaches on which I have spent time fossicking for stones in 2021. Photos of three stones I found on each beach are also included for each month. Part One examined the beaches of January to May and this Post examines the beaches of July to November (June and December feature close-ups of stones).

JULY, Timaru, 27 June 2021 – The Jack’s Point/Tuhawaiki Point Walkway runs along the cliffs above the central section of this South Canterbury beach. The northern part of the fossicking beach can be accessed from where Scarborough Road meets The Parade, just south of Timaru. Its southern part is accessible from the end of Ellis Road. There is a stretch of more than five kilometres of stones in between. See here for the beach on Google Maps. The photo in the Calendar was taken just south of the lighthouse on a day I accessed the beach from the Ellis Road carpark. The Post about my visit to that beach on 27 June 2021 can be found here.

AUGUST, Leithfield Beach, 11 March 2021 – There is a long stretch of beach that runs north and south of the Canterbury seaside settlement of Leithfield Beach, about 40 kilometres north of Christchurch. Interesting jaspers and petrified wood can be found here, slong with other kinds of stones. See here for the beach on Google Maps. I usually drive to the northern carpark, at the end of Elizabeth Square. The photo in the Calendar was taken from near the carpark, looking south towards an old storm water drain (which has recently started to be demolished). For an account of my visit to the beach on 11 March 2021, see here.

SEPTEMBER, Kai Iwi Beach, 2020 – This beach, at Mowhanau village, is only two kilometres away from where I live, near Whanganui in the North Island. It is not known for stones that can be tumble polished, indeed there are not a lot of stones along its sandy stretches, though various fossils have been found there. However, I am unable to resist a scanning of the beach when I walk it, and I have found a few interesting iron-stained pieces of quartz that I have tumble polished. Around the mouth of the Kai Iwi Stream is a particularly good place to search. See here for the beach on Google Maps. The photo in the Calendar is taken north of Kai Iwi Stream. An informative Post on the area is here.

OCTOBER, Gemstone Beach, 28 February 2021 – This beach is located about one kilometre west of Orepuki in Southland, on the coast of Te Waewae Bay. There is an amazing diversity of stones on the Te Waewae Bay beach, and the photo in the Calendar provides a good sense of this. See here for the beach on Google Maps. I ususally spend at least three hours on a visit, walking from the carpark at Mullens Road West along to the mouth of the Waimeamea River, near Waihoaka, and returning. For an account of my visit to the beach on 28 February 2021, see here.

NOVEMBER, Slope Point, 3 March 2021 – One of the small number of fossicking beaches just to the west of Slope Point in the Catlins is called Thunder Beach by some locals. It is a sweep of golden sand backed by a lagoon containing petrified logs. Access is across private land so permission should be sought. Here at the bottom of the South Island, the sea is often rough and waves are powerful. See here for the beach on Google Maps. Click this link for an account of my visit to the beach on 3 March 2021.

TumbleStone Calendar 2022 – The Beaches, Part One

2022 Calendar Cover
October
Kakanui, January
Slope Point, February
Riverton, March

The 2022 TumbleStone Calendar features ten photos of beaches that I have visited recently in order to collect stones to tumble polish. With one exception, these are South Island beaches visited on the date that the photo was taken (photos of three stones I found on that beach on that day are also included for each month). For the months of June and December, I feature close-ups of stones from the previous five months. In this Post, I provide the specific locations for January to May of each beach and link to any previous Post about the day I visited there. Part Two deals with the months of July to November.

JANUARY, Kakanui, 19 February 2021 – The location of this beach is two kilometres north of Kakanui village, a few kilometres south of Oamaru in North Otago. The beach sweeps northwards from a small roadside car park near the intersection of Seadown Road and Thousand Acre Road. See here for the beach on Google Maps. The photo in the Calendar was taken looking south towards the southernmost start of the beach. For the Post about my visit to that beach on 19 February 2021, see Day Three of this Post.

FEBRUARY, Slope Point, 12 & 18 June 2021 – This is one of a small number of fossicking beaches just to the west of Slope Point in the Catlins, the southernmost point of the South Island. Access is across private land so permission should be sought. The sea is often rough and tides are strong. This particular beach is known to at least some locals as Bach Beach because of a solitary holiday home overlooking it. It has a high cliff to the north which often keeps the beach in shade. See here for the beach on Google Maps. Click these links for my 2021 visits to that beach on 12 June and on 18 June.

MARCH, Riverton, 2 March 2021 – The Back Beach at Riverton/Aparima, Southland, is located along the last stretch of the Rocks Highway. It lies directly across Foveaux Strait from Rakiura/Stewart Island, so the tides are strong and swimming is not recommended. The photo in the Calendar is taken in a small bay at the western end of the Back Beach, right in front of the turning area at the end of the Rocks Highway, and looking towards the Howell Point Lookout. The three stones for March were collected just on the other side of the Lookout, on what I call the Beach Past the Back Beach. See here for the area on Google Maps. For the Post about my fossicking visit there on 2 March 2021, see Day 14 in this Post.

APRIL, Gemstone Beach, 18 & 19 September 2021 – This beach is located about one kilometre west of Orepuki in Southland which is about 20 minutes drive from Riverton/Aparima. Gemstone Beach lies on the coast of Te Waewae Bay, towards its eastern end, and large banks of stones run from there northwestwards for a number of kilometres. The photo in the Calendar is of the beach immediately in front of the carpark (on Mullans Road West), looking southeast, and includes a few fossickers – this is the direction towards Monkey Island and this part of the beach usually has very few stones. See here for the beach on Google Maps. I did not Post about my visits to Gemstone Beach in September 2021. However, a good idea of the beach and the area northwestwards is provided in this 2019 Post.

MAY, Ward Beach, 12 March 2021 – Ward Beach, Marlborough, is about six kilometres off the main road east from the small village of Ward in the Flaxbourne District, 82 kilometres north of Kaikoura and 45 kilometres south of Blenheim. The Flaxbourne River reaches the coast at Ward Beach, which is 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). The beach was uplifted by the 2016 Kaikoura earthquake, unveiling the boulders. The best part of the beach for stones is immediately in front of the car park, though it can be steep as it gets closer to the water and the incoming waves can be dangerous. The photo in the Calendar of the beach is looking north towards the carpark from near the Flaxbourne River mouth. The rocks in the foreground are visible only at low tide. See here for the beach on Google Maps. Regarding my visit to that beach on 12 March 2021, see Day 24 in this Post.

Continued in Part Two.

“S” is for “Slope Point Stone” and “T” is for “Timaru Today”

N is for November in the Calendar
O is for Opaque Orepuki Orbicular Jasper
P is for Planet in a Pebble
Q is for Quartzite Stone from Kakanui
R is for Riverton Rocks Red Rock

The following are my Posts for “S” and “T” in the weekly alphabetical series of a Facebook Group I belong to, “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Posts in this Series can be found here. The Series Index is here.

“S” is for “Slope Point Stone” – This tumble polished stone was collected by me earlier this year at a beach just west of Slope Point in Southland.

I initially thought it might be agatised tree fern. For example, in his book, “Agates of New Zealand”, Malcolm Luxton has a small section on Southland agates, and includes on page 292 a reference to “agatised tree fern sections” (see photo below). Two specimens are shown, one from Slope Point and one from Awarua Bay. The one from Awarua Bay looks very similar to the Slope Point stone I found. Jocelyn Thornton’s booklet, “Gemstones”, refers to this sort of stone on two different pages, the first on “Other Plant Material” (a section that follows ones on Petrified Wood, Agatised Wood and Opalised Wood), the second on “Beach Pebbles – Slope Point” (see photos below, the booklet is also online).

Malcolm Luxton, “Agates of NZ”.
“Agatised tree fern. Awarua Bay”. Page 292 of Malcolm Luxton, “Agates of NZ”.
From Jocelyn Thornton, “Gemstones”. http://www.peterthornton.com/files/nzgemstones.pdf
From Jocelyn Thornton, “Gemstones”. http://www.peterthornton.com/files/nzgemstones.pdf

However, it has been suggested that my initial tentative identification is likely to be incorrect. A member of the Group wrote: “I think the slightly circular patterns are more like spherulites than vascular bundles but that’s just my impression.” This would probably make it more likely that the stone is rhyolite. Either way, this is a very intriguing stone. Slope Point is the southernmost part of the South Island mainland, just a few kilometres west of the better-known Curio Bay (a reserve where you can view a rock platform of trunks of petrified trees from the Jurassic). The beaches just to the west of Slope Point are also known for their petrified wood (much of it black) as well as a range of varieties of rhyolite. See here for an Introduction to Slope Point.

“T” is for “Timaru Today” – One of the stones I found today on a Timaru beach as I was passing by on my way south.

Probably a green quartzite – these are often to be found on this beach. I accessed the beach by turning off State Highway One onto Scarborough Road, just south of Timaru.

Access to the beach is at the end of Scarborough Road, at the start of the Jack’s Point Lighthouse walkway.
Around the first corner of the beach when walking southwards – Jack’s Point lighthouse.
Looking north towards Timaru.

I first visited here in early June, after reading on this Facebook Group about a couple of local fossickers who spend time at this beach.

For the next Post in this Series, see here.

Oliver’s Fossil Coral Stone

Oliver on a Slope Point beach, in winter.
Slope Point area. Source: Google Maps.
A Slope Point beach on a fine day.

Oliver Simpson found this stone on a Slope Point beach at the bottom of the South Island. When he first showed it to me, I could see nothing in it. He then pointed to some very faint markings and mentioned “coral”. I don’t know whether the stone warmed in my hand and as a result showed the outlines of the coral septa (radiating plates as seen from above) more clearly, but I could then start to make out the faint shapes distinctive to coral.

Oliver’s fossil coral, before tumbling.
Oliver’s fossil coral, before tumbling.
Oliver’s fossil coral, before tumbling.

A previous Post on fossil coral can be found here.

Oliver’s stone is a rare and enigmatic stone, rare because it is fossil coral, enigmatic because it does not seem to show itself easily in person. Oliver and I discussed whether it would be worth tumbling the stone, to bring out the coral shapes more clearly. I was reluctant to do anything to spoil such a rare specimen, but in the end I agreed to give it a go. I tumbled it in a very fine 600 grit for 9 days to see if any improvement occurred.

After 600 grit tumble.
After 600 grit tumble.

Removal of a very thin surface layer brought out the coral shapes in a brighter white. However, I was not keen to try more as I did not think further “improvement” or clarity could be achieved. So the stone then went into a pre-polish then a pro-polish tumble:

The end result is still enigmatic, and lacks some of the subtle beauty of the original stone. While the shapes of the coral can be seen more clearly, they appear harsh and not always cleanly defined.

Twenty-Four Slope Point Stones Polished for Oliver: Part 2, Stones 11 to 24

At the beginning of August, I finished tumble polishing 24 stones that Oliver Simpson had collected from Slope Point beaches (Southland). Part One looked at Stones #1 to #10. This Post presents images of the remaining 14 stones.

The 24 stones in the first batch I polished for Oliver.
The sign at the top of the cliffs at Slope Point.
Oliver on a Slope Point beach.

Stones #11 and #22 appear to be some kind of fossilised material, maybe fern. Such material has really interesting patterns:

Stone #11, Side A.
Stone #11, Side B.
Stone #22, Side A.
Stone #22, Side B.
Stone #22, Side C.

Stone #15 is a small piece of petrified wood with maybe some chalcedony-agate material in it:

Stone #15, Side A.
Stone #15, Side B.
Stone #15, Side C.
Stone #15, Side D.

Another highly interesting stone is #19, with one dark side and one light side, and with other material within it:

Stone #19, Side A.
Stone #19, Side A.

There are five light-coloured petrified wood stones, with one of them, #21, containing some breccia as well:

Stone #21, Side A.
Stone #21, Side B.
Stone #21, Side C.

The other four light-coloured pieces of petrified wood are Stones #14, #17, #23 and #24:

Stone #14, Side A.
Stone #14, Side B.
Stone #17, Side A.
Stone #17, Side A.
Stone #23, Side A.
Stone #23, Side B.
Stone #24, Side A.
Stone #24, Side B.

There are four dark-coloured petrified wood stones, #12, #13, #16 and #18. Stones #13 and #16 include some interesting white markings:

Stone #13, Side A.
Stone #13, Side B.
Stone #16, Side A.
Stone #16, Side B.

Stones #12 and #18:

Stone #12, Side A.
Stone #12, Side B.
Stone #18, Side A.
Stone #18, Side B.

The remaining stone is #20, a small caramel-coloured one:

Stone #20, Side A.
Stone #20, Side B.

Twenty-Four Slope Point Stones Polished for Oliver: Part 1, Stones 1 to 10

At the beginning of August, I finished tumble polishing some stones that Oliver Simpson had collected from Slope Point beaches (Southland). This is an area known for its black petrified wood, including tree ferns (ponga), and rhyolites. Jocelyn Thornton has a page on Slope Point stones in her booklet “Gemstones” (see page 35 here). Oliver is particularly interested in the petrified wood and often collects large pieces.

The 24 stones in the first batch I polished for Oliver.
Slope Point area. Source: Google Maps.
The sign at the top of the cliffs at Slope Point.
High cliffs and rough sea at Slope Point.

After we did a couple of fossicking trips to Slope Point beaches in June (see my Posts for 12 June and 18 June), Oliver showed me a number of his finds from over the years. I offered to tumble polish a few and he entrusted me with some of his smaller stones, many of them really fascinating. He also gave me to tumble a fossil coral he found at Slope Point and an unusual chalcedony stone from near Moeraki Village in North Otago (these will feature in future posts).

The first batch that I finished tumble-polishing numbered 24 stones (see photo above). Most had started with one or two tumbles in 400 grit, the grit and polish stages all being completed on 8 August. The largest stone, Stone #1, is about 4.5 cms long.

One of the beaches to the immediate west of Slope Point.
A Slope Point beach on a fine day.
Oliver on a Slope Point beach.
Some of Oliver’s rock finds.

Here are the first 10 of these:

#1
#2
#3
#4
#5
#6
#7
#8
#9
#10

Stones #2 and #3 are perhaps the most spectacular and interesting. Stone #2 has a broken pattern of different colours with bright white agate-looking material at the top and bottom:

Stone #2, Side A.
Stone #2, Side B.
Stone #2, top.
Stone #2, bottom.

Stone #3 is an excellent example of fossilised tree fern material. The close-ups reveal exquisite complexity:

Stone #3, Side A.
Stone #3, Side B.

Stone #6 is another with intriguing markings:

Stone #6, Side A.
Stone #6, Side B.

Stones #1, #8 and #10 are similar pieces of petrified wood, very dark in colour for most of the stone but with some brown areas that reveal the wood. Stone #1:

Stone #1, Side A.
Stone #1, Side B.
Stone #1, Side C.

Stone #8 has some interesting areas of wood grain:

Stone #8, Side A.
Stone #8, Side B.
Stone #8, Side C.

Stone #10 has a prominent light-coloured band on one side:

Stone #10, Side A.
Stone #10, Side b.

Finally, four of the stones are petrified wood of different hues but with a light-coloured vein within them. Stones #4 and #5 are similar in having areas of light grain. Here are images of four sides of Stone #4:

Stone #4, Side A.
Stone #4, Side B.
Stone #4, Side C.
Stone #4, Side D.

And three sides of Stone #9:

Stone #9, Side A.
Stone #9, Side B.
Stone #9, Side C.

Stones #5 and #7 are much darker in colour, so their white veins stand out more. Stone #7 in particular has an intriguing band, maybe quartz:

Stone #5, Side A.
Stone #7, Side A.
Stone #7, Side B.
Stone #7, Side C.

Part Two on the rest of the stones can be found here.

National Lockdown Number Two: Stone 14

The last Stone-of-the-Day for this National Lockdown is a small conglomerate stone from Slope Point (bottom of the South Island) that I found in June and finished tumble polishing two days ago.

Side A.

It is amazingly complex, and has polished well, apart from a couple of tiny rough patches.

Side B.
Side C.

Most of New Zealand, including my home area of Whanganui, drops to Alert Level Three tomorrow (1 September). This level continues to have a lot of restrictions, but will be reviewed in one week’s time. Auckland is still experiencing new daily cases of the Delta variant of Covid-19, though they are starting to decrease slowly, 53 yesterday and 49 today, and will remain at Alert Level Four, Lockdown, for at least another two weeks.