Month: May 2021

FB Group Posts: 26, 27 & 28 May 2021 – Kakanui Quartzites and Slope Point & Gemstone Beach Stones

This is the eighth in this Series reproducing my recent regular Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.

Tuesday 25 May 2021: This is the day I made a Post in the Group’s Alphabetical Series – “D” is for “Dendrites” – see this Post.

Wednesday 26 May 2021: Four small quartzite stones from Kakanui, recently tumble-polished. Between 2.5 cms and 3.5 cms in size, varying colours.

Red Kakanui quartzite.

Some research over the last couple of days has led me to the following: Quartzite is usually a metamorphosed sandstone. The intense heat and pressure of metamorphism causes the quartz grains to compact and become tightly intergrown with each other, resulting in a very hard and dense quartzite – see photo of quartzite under a microscope below (from https://www.alexstrekeisen.it/english/meta/quartzite.php – the very tightly packed quartz grains in this photo range in colour from white to gray to black depending upon their optical orientation).

The stones on the beach near Kakanui where I found these four small quartzites.
Microscopic view of quartzite from http://www.alexstrekeisen.it/english/meta/quartzite.php. Very tightly packed crystals. The colour of the crystals depends on their orientation to the view.
Page 34 in Thornton’s “Gemstones” https://www.onnaturesedge.co.nz/downloads/nzgemstones.pdf
Reference to “Quartzite from Central Otago”.

Geology.com reports that quartzite is usually white to gray in colour – if stained by iron, it can be pink, red, or purple, while the presence of other minerals can cause quartzite to be yellow, orange, brown, green or blue (see https://geology.com/rocks/quartzite.shtml). In her page on beach pebbles from Moeraki-Kakanui in “Gemstones”, Jocelyn Thornton includes a “Quartzite from Central Otago”, and the photo is of a stone very similar to Stone 3 (see photos above) – see page 34 here. On page 20, “Other Varieties of Silica”, Thornton notes: “Quartz sands cemented by silica make an extremely hard and durable quartzite which is found on some hillsides in Central Otago and washed down rivers and out along the coasts. These quartzites have cloudy patterns and take a very good polish.”

Thursday 27 May 2021: Three small recently tumbled stones from a beach near Slope Point in the Catlins, Southland. 2 cms to 4 cms in size. Jocelyn Thornton writes of Slope Point: “On the Southland coast between Waipapa Point and Haldane there are a few pebbly beaches visited by fishermen and rock collectors. The cliffs contain layers of conglomerates with pebbles which weather out and collect on the beaches. At first glance they appear dark, but closer examination reveals a multitude of subtle colours and patterns” (page 35 here).

Interesting lines and patterns.
Opaque stone (not transparent).
Rhyolite.
The three small stones.
The beach just west of Slope Point, where the stones were collected.

Friday 28 May 2021: Small Gemstone Beach (Orepuki, Southland) polished stone, 3.5 cms long, collected earlier this year. Came out of a tumble barrel yesterday. Striking green lines.

Other side of stone.

[A comment on this Post from a resident of Scotland: “Love those epidote patterns, John. I am amazed that we have conglomerate cobbles from a Mississippi type delta down the Angus coast of Scotland that mirror the ones you post. These originated in Greenland/ N America poles apart”.]

The next Post in this Series is here.

“C” is for “(Fossil) Coral” and “D” is for “Dendrites”

A is for Amygdaloidal
B is for Botryoidal
C is for (Fossil) Coral
D is for Dendrites
E is for Entrance

Recently the Facebook Group I belong to, “New Zealand Lapidary, Rocks, Minerals, Fossils”, invited its members to submit photos each week of a stone, mineral or fossil in their collection that starts with a letter of the alphabet. My Posts for the first two letters can be found here. The following are my next two Posts in the series.

“C” is for “(Fossil) Coral” – I found this fossil coral stone on Gemstone Beach (Orepuki, Southland) on 10 June 2020. My sister was showing me a stone she had found when I looked down and saw this stone with faint unusual markings. Not only the top of the corals can be seen but also the view from the side. I have not seen anything like it before on Gemstone Beach, nor since.

Top of the polished coral fossil stone.
Side view of polished coral fossil stone.
Top view of fossil coral stone when found on Gemstone Beach.
Side view of fossil coral stone when found on Gemstone Beach.

Of the fossil corals, there appear to be two types (families) which this stone could belong to – rugose and scleractinian. They both have “septa”, the radiating segments seen from the top. But the symmetry in rugose is bilateral, meaning that two identical halves can be created, while scleractinians have radial symmetry (reflecting two different types of growth processes). See Palaeo Post. The well-known Petoskey stone, the official stone of the US State of Michigan, is a rugose coral – the photo of a polished Petoskey stone below is from http://www.geologyin.com/…/what-is-petoskey-stone-and…
I have also posted below two diagrams from Wikipedia, showing the rugose (“tetracorallia”) and scleractinian (“hexacoralla”) corals from a 1904 book.

Polished Petoskey stone from Michigan http://www.geologyin.com/…/what-is-petoskey-stone-and….
Drawings of rugose corals from 1904 book – from Wikipedia. Source: https://en.wikipedia.org/wiki/Rugosa
Drawings of scleractinian corals from 1904 book – from Wikipedia. Source: https://en.wikipedia.org/wiki/Scleractinia
Entry for a rugose coral on page 29 of “A Photographic Guide to Fossils of NZ”

To my eyes, my stone looks closer to the rugose family but I am far from certain, given the great diversity within each family type. The book “A Photographic Guide to Fossils of NZ” has an entry (p.29) for a rugose coral (see above) (one of a total of six entries for coral fossils in the book). The stone I found on Gemstone Beach has tumble-polished well, with just one small shallow hole to interrupt its smoothness.

I failed to anticipate how much attention this Facebook Post would receive from the members of the “New Zealand Lapidary, Rocks, Minerals, Fossils” Group. The week after the Post, it was given 53 “Wow”, 78 “Love” and 176 “Like” along with more than 50 Comments about its beauty and interest. The Administrators of the Group decided to make it the Group banner for a while.

I was not happy with the photos I had used for the Facebook Post, the close-ups in particular looked too yellowish. So I took some more photos and tried to produce better close-ups. I wrote: It is a difficult stone to photograph as it is curved, and focus plus lighting are difficult (I use my camera’s automatic settings). I have tried again but don’t know if these are much of an improvement. Creating the close-ups seems to accentuate the yellow tinge, and I have tried to adjust for this, without much success. However, interesting aspects of the coral structure can still be seen.

A few days later, I was searching for information on the geology of Slope Point, to provide some context for the rhyolite stones I found there. In one book I consulted, “The Natural History of Southern New Zealand”, I came across a reference to fossil coral at Te Waewae Bay. Gemstone Beach is located towards the eastern end of Te Waewae Bay. The following is stated on pages 62 and 63 of the book, in Ewan Fordyce’s outstanding chapter on “Fossils and the History of Life”: “Te Waewae Bay rocks yield the only specimens of a bizarre pseudo-colonial form of sceleractinian coral apparently related to Flabellum… [It sits in the] siltstone of the Te Waewae Formation; probably upper Kapitean, latest Miocene; western Te Waewae Bay.”

Te Waewae Bay coral fossil, related to Flabellum. Page 63, “The Natural History of Southern NZ”
Living Flabellum coral, photo by Nick Hobgood. Source: https://en.wikipedia.org/wiki/Flabellum_(coral)
Cover of “The Natural History of Southern NZ”
Page 63, “The Natural History of Southern NZ”
Flabellum coral fossils, esp. A & B. Source: https://www.mindat.org/paleoimg.php?id=1282846

Note: “The Natural History of Southern New Zealand” is edited by John Darby, R. Ewan Fordyce, Alan Mark, Keith Probert and Colin Townsend, published in 2003 by University of Otago Press. Currently available from University of Otago Press for $80.

Coral of the Flabellum family are fan-shaped, usually solitary, and seem quite different from the fossil coral I found – see NIWA Critter of the Week., Mindat Fig. 4 (esp. A & B) and Mindat Fig 5. I have not yet come across any other reference to fossil coral found along the south coast.

To return to the alphabetical series of Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils” – I posted the following on 25 May 2021:

“D” is for “Dendrites” – I found this stone in March 2021, on a beach not far from my motel on the northern side of Kaikoura town, while I was looking for stones with trace fossils (zoophycos). The stone is probably a limestone(?) or mudstone(?), too soft for tumble polishing. The word “dendrite” is from the Greek word for “tree”, referring to its branching. In geology, dendrites are thin, branching crystals, often of some variety of manganese oxide (or iron), that grow over a surface in a rock or mineral. They are found in cracks or along bedding planes.

Unpolished Kaikoura stone with dendrites.
The beach at north Kaikoura where the stone was found. Kaikoura town centre is at middle right of photo.

See Mindat for some good photos of dendrites https://www.mindat.org/min-26645.html. See Sandatlas for a technical explanation of their growth https://www.sandatlas.org/dendritic-growth-in-crystals. Jocelyn Thornton provides some NZ examples of dendrites in agates in her book “Gemstones” – see page 15 here (see photo below). Dendrites are often given as examples of “pseudofossils”, natural objects that may be mistaken for fossils (of a plant leaf, for example) – see https://www.dmp.wa.gov.au/Pseudofossils-1663.aspx

Jocelyn Thornton’s “Gemstones”, pages 30-31 in book, page 15 in online version https://www.onnaturesedge.co.nz/downloads/nzgemstones.pdf
Dendrites in agates, close-up of Jocelyn Thornton’s book.
Mindat entry https://www.mindat.org/min-26645.html
From Sandatlas https://www.sandatlas.org/dendritic-growth-in-crystals/
From “Pseudofossils”, Western Australia Dept of Mines, Industry Regulation and Safety https://www.dmp.wa.gov.au/Pseudofossils-1663.aspx

For “E” and “F”, see this Post. The Series Index is here.

FB Group Posts: 22, 23 & 24 May 2021 – Kakanui Jaspers, Agates and Quartz

This is the seventh in this Series reproducing my recent regular Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.

Saturday 22 May 2021: Four small tumble-polished jaspers from a beach near Kakanui, collected in February-March this year, just out of the tumbler. 2 to 2.5 cms size. These illustrate just some of the diversity of jaspers from that beach.

The south end of the beach near Kakanui where I found these small jaspers.

Sunday 23 May 2021: Shining the light on (or through) three recently tumble-polished stones from a Kakanui Beach. Two beach agates (chalcedony) and one stained quartz.

Stone 1, beach agate (chalcedony) with cream-coloured markings, 3.5 cms long.
Another side of Stone 1.
Stone 1 held up to a sunny sky.
Stone 2, stained quartz stone, 4.5 cms long. The stone is actually very smooth and polished, not well conveyed in the photos.
Stone 2 with a torch behind it.
Other side of Stone 2.
Other side of Stone 2 with a torch behind it.
Stone 3, beach agate (chalcedony). 5 cms long.
Stone 3 held up to a sunny sky.

Monday 24 May 2021: Gorgeous jasper from a Kakanui beach – 5.5 cms by 4 cms in size. Found at 12.42 pm on 19 February this year (according to the time stamp on a photo I took of it then). The stone looked astounding on the beach. (See Day Three in this Post.) After tumbling, it has taken a very good polish, not shown well in the photos.

One side of the polished stone. It actually looks a lot better than this.
Other side of the polished stone.
Photo of the wet stone when found on the beach.
Photo of the wet stone when found on the beach.
The beach near Kakanui where the stone was found. Looking north towards Oamaru.

I started it in 400 grit and gave it only a week there before putting into polish. The end product has four or five small rough areas, which could have been smoothed away with more tumbling in grit but I wanted to keep its size and character. The close-ups don’t really do it justice. The photos taken on the beach when I found it are stunning and in many ways better represent how the stone looks now.

The next Post in this Series is here.

“It’s About Time!” How Long Should I Leave My Stones Tumbling in a Barrel?

Four 3lb barrels tumbling.
Tumbling Log entry.
Polished Kakanui quartzite stone.
Kakanui fossil hash stone after 400 grit tumble.

Time management is an important part of tumble polishing. There exist guidelines for how long each stage should take, whether it be grit or polish or burnish. For example, it is generally recommended that you tumble stones for about a week in each size of grit. I have followed this approach in my series of Posts “The Seven Stages in Tumble Polishing Stones”. I keep a tumbling log for each batch of stones, recording the day and time it starts. That way, I can see when the week is up.

However, it is also advised that some stones may need more than a week in, say, 220 or 400 grit. I sort through the stones after each tumble and decide which ones are ready to go to the next stage, which ones need to repeat the stage, and maybe which ones would benefit from going back a stage.

It is difficult to be patient, to wait until the time is up. I try hard to add an extra day or so to the usual week for most stages, but don’t always succeed. Also, I have slipped into the practice of burnishing with borax for only two or three days instead of a full week. And I have been thinking everything has been going ok.

Two things have given me pause recently, have forced me to rethink my approach to timing. The first was a batch of stones that I noticed were polished better than usual. It was a group of Kakanui stones that had just finished polishing in a 3lb barrel. I was pleasantly surprised to see how shiny they were.

The 3lb barrel batch of polished Kakanui beach stones.
Polished Kakanui quartzite stone.
Polished Kakanui quartz stone.
Even this jasper came out really well when often jaspers can look a bit “flat”.
I didn’t expect this stone to polish well because of its different materials – but I was pleased with how well it turned out.
My tumbling log entry for this batch of stones.

I checked in my tumbling log. They had spent 10 days in pro-polish and six days in borax. The extra time was because I had been busy doing other things. I don’t actually know for sure if the extra shininess of the stones is due to some quirk of my current perception, or the couple of extra days in pro-polish, or the longer than usual time in borax. The pro-polish mixture had been used three times before, so the cause was not fresh polish.

I am now more of a mind to give the polishing tumble stage a bit more time and to make sure the burnishing tumble in borax goes at least close to the full week.

The second thing that has caused me to rethink timing issues was when I was recently asked a question by email about the use of grits and polishes for a larger barrel than usual. After providing information about different grits, different barrels and tumbling times for different stages, I added something I remembered when I visited an older and experienced tumble polisher about four years ago. I wrote: “He said that sometimes he simply puts stones into coarse grit and tumbles them for a few weeks – his notion is that the grit breaks down, just as the stones do, and the grit gets finer as the process proceeds, and he ends up with smooth stones at the end.” I have come across this idea a couple of other times, and it was recently repeated in a conversation I had a couple of days ago with another tumble polisher. I may experiment with this approach myself one day but, in the meantime, I am certainly encouraged to give my barrels more time.

There are exceptions to every guideline. There is an interesting stone I find at Kakanui that comes from an ancient fossilised seabed – it is also known as fossil hash. It is kind of grainy, not smooth or shiny. l have discovered that after up to a week in 400 grit, it feels smooth and waxy. Any longer doesn’t improve it and starts to reduce it in size significantly. Polishing doesn’t improve the stone at all, so it is at its best after the 400 tumble.

Some rough fossil hash stones found at Kakanui.
Fossil hash stones after a week’s tumble in 400 grit.
Before…
…and after.
Kakanui fossil hash stone after 400 grit tumble.

In this case, less time tumbling is the right thing to do. But this is an exception.

FB Group Posts: 18, 20 & 21 May 2021 – Birdlings Flat Beach Agate and Slope Point Stones

This is the sixth in this Series reproducing my recent regular Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.

Tuesday 18 May 2021: Another recently tumble-polished small beach agate (chalcedony) from Birdlings Flat. Not banded this time. I decided to try to retain some of its outer character so did not wear away all of the brown and white material in the tumbler – and the result is very interesting. The stone is 3.5 cms long, having some small indentations but otherwise smooth.

One side of the polished stone.
Other side of the polished stone.
Held up to a sunny sky.

Wednesday 21 May 2021: This is the day I made a Post in the Group’s Alphabetical Series – “C” is for “Coral” – see this Post.

Thursday 20 May 2021: A small tumble-polished rhyolite from Slope Point (southern-most point of the South Island). Collected there on 3 March during a visit with Oliver Simpson [see previous Post]. Its wavy lines caught my eye on the beach.

It is a small stone.
One side of the polished stone.
Treasure
Another side of the polished stone, with a rough area apparent.
The beach near Slope Point on which the stone was found. To the right is the edge of a lagoon, with the open sea to the left (and ahead).
Oliver Simpson on the beach – many thanks to him for the day’s outing.

It has come out of a 3lb barrel this morning, my first completed batch of Slope Point stones. This stone is only 3 cms long and 1 cm wide. Because of its smallness, I didn’t completely smooth it before putting it into polish, doing only one week in 400 grit before a pre-polish and pro-polish

Friday 21 May 2021: Three small tumble-polished stones from my first (and so far only) fossicking visit to Slope Point (southern-most piece of land of the South Island), collected in early March, finished polishing yesterday.

Stone One, about 2.5 cms.
Another side of Stone One.
Stone Two, 4 cms long.
Other side of Stone Two.
Stone Three, 3 cms.
This sign stands at the place that the tourists get directed to. Fossicking beaches are nearby but not easy to access.
Slope Point and adjacent beaches. Source: Google Maps.

The next Post in this Series is here.

“You are always staring at the ground!” “What you got?” Detectorists and Rockhounds – Lyrical Musings

Danebury Metal Detecting Club, from “Detectorists”. Source: https://www.netflix.com/nz/title/80065658
Always staring at the ground… Source: http://www.theaustralian.com.au
“Detectorists” on Netflix. Source: https://www.netflix.com/nz/title/80065658
Theme Song of “Detectorists”. Source: http://www.tunescribers.com/4935/more-catalog/detectorists

There are a lot of similarities between rockhounds and detectorists. Both are always looking for “treasure”. Both pursuits have solitary aspects to them, though they are often undertaken with a mate. Both have their own clubs, though they rarely thrive (though New Zealand rockhounds have some exceptions to this). Both have their own technical languages and seemingly arcane knowledge. Both involve passions and obsessions not understood by others. And the list could go on.

I really enjoyed watching the British comedy programme “Detectorists”. It was written and directed by the brilliant Mackenzie Crook, who also plays a leading role alongside Toby Jones. The programme revolves around the lives, loves and metal detecting ambitions of Andy and Lance, members of the Danebury Metal Detecting Club of northern Essex. Two of the strengths of the programme are its characters and its humour (including some ribald quips now and then). Below is the trailer for Series One (three series were made), which first aired on BBC Four in 2014 (Warning: Occasional effective use of bad language!):

“Detectorists” is remarkable for its quiet insights into the life of ordinary English people who happen to share an obsession, metal detecting. The detectorists spend hours in the open in all kinds of weather, looking for something that excites them immensely but which they rarely find, while the rest of life passes them by, unnoticed. I think that Robert Lloyd of the “Los Angeles Times” has captured much of the essence of “Detectorists” – “Like the ordinary lives it magnifies, Detectorists has the air of seeming to be small and immense at once, to be about hardly anything and almost everything. It is full of space and packed with life.” Ben Dowell of “The Times” described the show as being “steeped in a gentle kindness that I hadn’t seen before”. (For the source of these quotes and for more details about “Detectorists”, see Wikipedia.) The first two Series are available on Netflix in New Zealand.

The theme song for “Detectorists” was written and sung by Johnny Flynn. This version, on YouTube (see below), has the following lyrics:

Will you search through the loamy earth for me
Climb through the briar and bramble?
I’ll be your treasure

I felt the touch of the kings and the breath of the wind
I knew the call of all the song birds
They sang all the wrong words
I’m waiting for you
I’m waiting for you

Will you swim through the briny sea for me
Roll along the ocean’s floor?
I’ll be your treasure

I’m with the ghosts of the men who can never sing again
There’s a place, follow me
Where a love lost at sea
Is waiting for you
Is waiting for you

Would you drift o’er the rolling fields for me
Hoard me in the highest bough?
I’ll be your treasure

But in history’s rhyme there’s a place and a time
And a truth to the gold that the folds cannot hold
I’m waiting for you
I’m waiting for you

I decided to to write a set of alternative lyrics for rockhounds, especially those like me who spend hours on beaches, staring at the ground. It took me a few weeks to put them all together – they are not perfect but I had fun doing them:

Rockhounds

Will you hunt on the stony beach for me
Search through the drifts of pebbles?
I’ll be your treasure

I spied the flash of white Quartz and the grain of Pet Wood*
I saw the hues of all the Quartzites
But waves swept them from my sight
I’m waiting for you
I’m waiting for you

Will you wade through the gravel stream for me
Andesite and Jasper seek?
I’ll be your treasure

I’m with the stones just below, you can never let me go
Epidote, Argillite, Serpentine, Rhyolite
Are waiting for you
Are waiting for you

Would you fossick near the pounding waves for me
Hide me in your heavy bag?
I’ll be your treasure

But when you get me back there’s no place to unpack
And your stones are like gold that you have and must hold
I’m waiting for you
I’m waiting for you

*Note: “Pet Wood” in rockhound circles is shorthand for “Petrified Wood”.

Treasure
Treasure
Treasure
Treasure
Treasure
Treasure
Treasure
Treasure

A search of YouTube reveals bits and pieces from “Detectorists”. For example, there is an extract about the time, right at the end of a day’s detecting, when Lance finally finds a valuable artefact and dances his “gold dance” (rockhounds do this too – decide to stop when it is late in the day, but then just have to search another five minutes in case a “treasure” is sitting there waiting on the next metre or two of beach or ground – and we all have our own idiosyncratic reactions when we finally find “treasure”). At the start of the extract, Andy is telling his friend Sophie that he is going overseas for a year with his wife and baby, taking part in an archeological dig while his wife teaches:

“When in doubt, dig it out!” If it catches your eye, don’t ask why – pick it up!”

FB Group Posts: 15, 16 & 17 May 2021 – Birdlings Flat “Polish Failure”, Another Birdlings Flat Quartzite, and Birdlings Flat Banded Agate

This is the fifth in this Series reproducing my recent regular Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.

Saturday 15 May 2021: The failure to polish… There are two processes I enjoy – finding interesting stones, and seeing them tumble-polished. The first does not always lead to the second – sometimes a stone does not polish, or not very well. After a few years’ experience, I have a good idea which stones will polish and which will not. Then there are those stones that look really interesting but I kinda guess they may not polish. Some I try anyway – because the stone is so interesting, and I have hope. I found this stone on Birdlings Flat on 24 August 2020 and finishing polishing it two days ago. It is 3.5 cms long.

One side of the polished stone.
Closer image of the polished stone.
Other side of the polished stone.
The stone as originally found on Birdlings Flat.

It didn’t really polish, but remains fascinating and will be kept in my collection. It is volcanic, [probably andesite], would originally have had lots of holes in it, and these holes have filled with minerals as water moved through over thousands and thousands of years. Generally, the infill material polished much better than the host material.

[Comments on this Post included “Some of the infill is banded and is tiny agates… Pretty red matrix too”, “Likely originated from the Rangitata River” and “See these in the Hinds River too. Varying sizes”.]

Sunday 16 May 2021: Birdlings Flat quartzite, recently tumble-polished, 5.5 cms long, still 3 or 4 very small areas of shallow rough places on it but I didn’t want to reduce it in size any more. It is far to interesting to me in its complexity to risk losing some of that by further tumbling.

Monday 17 May 2021: Banded beach agate, Birdlings Flat, just finished tumble-polishing. Five cms long, polished to a very smooth finish. I was amazed that the small marks caused by bashing against other stones and rocks in the waves actually seem to go quite deep, were not removed by tumbling (400 grit then polish).

One side of the polished stone.
Treasure
Held up to the sunny sky.
With a torch behind it.

The next Post in this Series is here.

New Website for Rotorua Lapidary Supplies

The new website https://www.rockandgemstoneshop.co.nz.
“Lortone Tumblers” from the new website.
The shop’s other current online presence https://rotorua-lapidary-rock-and-mineral-supplies.business.site.
From old website https://www.rotorualapidary.co.nz.
Old website https://www.rotorualapidary.co.nz, as found on https://web.archive.org.

This shop, at 1120 Eruera Street in Rotorua, known as the Rotorua Lapidary Rock and Mineral Store, is the dealer for Lortone rock tumblers and gemstone manufacturing machinery in New Zealand, having had this role for over 35 years. The store now has a new online shop. The former url http://www.rotorualapidary.co.nz takes you to the new website (or else it does not work). The new url is www.rockandgemstoneshop.co.nz. The shop is now called Rotorua Rock and Gemstone Shop. I have also come across another online presence at https://rotorua-lapidary-rock-and-mineral-supplies.business.site – this is just slightly different in layout.

I have referred to the old website many times on Tumblestone Blog as the shop is the source of my tumblers, grit, plastic pellets, etc. I will slowly replace the old website url with the new in these previous Posts. The Rotorua Shop provides great service and responds very promptly when anything is ordered from them. I have always been impressed with them.

FB Group Posts: 12, 13 & 14 May 2021 – A Back Beach Breccia and Two Birdlings Flat Quartzites

This is the fourth in this Series reproducing my recent regular Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.

Wednesday 12 May 2021: Tumble-polished stone (6.5 cms long) from the Back Beach, Riverton/Aparima. In some ways, a very ordinary looking stone. A closer look reveals complexity, subtlety, beauty. [Probably a breccia stone, made up of fragments in a fine-grained matrix.]

The Back Beach, at the end of the Rocks Highway, Riverton/Aparima. On Foveaux Strait, across from Stewart Island/Rakiura. Source: zoomin.co.nz.
The Back Beach, hit the by swells of Foveaux Strait. Great for tumbling stones the natural way!
The stones at the western end of the Back Beach.

Thursday 13 May 2021: Small Birdlings Flat quartzite, just out of the tumble-polisher this morning, collected sometime between one and two years ago. Very smooth, nice colours, 3 cms long.

Treasure

Friday 14 May 2021: Another Birdlings Flat quartzite that finished tumble polishing yesterday, 5 cms long, very smooth except for one small shallow crack along the side. I wasn’t sure what it was until I did the close-ups. Interesting iron staining.

[I added a comment to this Post: “I think the grey colour of the stone, like most of this is, is kinda the neutral base for the yellows and reds. At least, that is the thought that has been going around in my mind for a couple of years now”, and a Group Member replied: “I too have looked at them and thought it’s as though different colours, in varying degrees of coverage, have been washed over a grey base. I’ve also looked at the stones I have of that type and wondered if some of the variation was due to them being at different stages of formation or ocean tumbling…”]

The next Post in this Series is here.

FB Group Posts: 8, 10 & 11 May 2021 – Helen’s Stones, Gemstone Beach Stones, and Riverton/Aparima Stones

Here are three more of my recent Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.

Saturday 8 May 2021: Ten selected tumble-polished stones from a 4lb barrel. These stones were found on Gemstone Beach (Orepuki, Southland) by my sister Helen who sometimes accompanies me on my fossicking trips. All are currently in the post to her in Gore.

Quartz stone with black mineral inclusions.
Same stone with a light behind it.
Volcanic, some amygdales.
Probably argillite, with a small mica flake at top.
One of the smaller stones.
Another small stone.
The larger stones in the 4lb barrel. Largest would be about 6 cms.
The smaller stones in the 4lb barrel, $2 coin at top right for size.

Sunday 9 May 2021: This is the day I made a Post in the Group’s Alphabetical Series – “B” is for “Botryoidal Chalcedony” – see this Post.

Monday 10 May 2021: Someone once wrote: “A smooth striped stone found in the bottom of my coat pocket transports me back to a beach walk. I can hear the pebbles crunching underfoot, and imagine the view out to sea as I make my way slowly along, scanning the tideline, which is tumbled with shells, driftwood, seaweeds and tattered feathers…” (page 7 of Angie Lewin’s “Introduction” to “The Book of Pebbles: From Prehistory to the Pet Shop Boys”, written by C. Stocks, illustrated by A. Lewin, 2019). Below are photos of six tumble-polished stones, collected on Gemstone Beach (Orepuki, Southland) earlier this year. Just out of the barrel yesterday.

Quartzite.
Probably iron-stained quartz/quartzite.
Volcanic stone with crystals, probably a porphyry composed of black basalt and white feldspar.
Probably a small quartzite.
On the beach, this looked like petrified wood, but is probably quartzite again.
Another quartzite, the intense green likely to be epidote.

Tuesday 11 May 2021: Six small tumble-polished stones from Riverton/ Aparima, Southland. I picked up these at places like the Back Beach, the beach just beyond the Back Beach, and Henderson Bay.

The six small tumble-polished stones from Riverton/Aparima.
Not sure what kind of stone this is.
Jasper-agate.
Could be quartzite.
A different type of quartzite.
Likely to be yet anaother type of quartzite.
Don’t know what this stone is.
Back Beach, Riverton/Aparima.
The Back Beach is just around the corner from here.

Riverton/Aparima is situated 30 kms east of Gemstone Beach (Orepuki) and 40 kms west of Invercargill. This small town is the oldest pakeha settlement in Southland, a whaling station having been established there in the mid-1830s with land-based economic activity replacing that by the 1850s. Riverton Rocks (Taramea Bay, Mitchell’s Bay and Henderson Bay) became an important seaside holiday destination. My grandparents owned a crib (bach) at Henderson Bay from the late 1950s/early 1960s and I spent many Christmas holidays there.

The next Post in this Series is here.