A Blog About Stone Gathering, Tumbling and Polishing, and Rocks and Landscapes, from New Zealand – With Musical Interludes (john.tumblestone@gmail.com)
A 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. The first Posts in this Series can be found here. The following are my Posts for “G” and “H”.
“G” is for “Green Hydrogrossular Garnet from Gemstone Beach”. Found on Gemstone Beach (Orepuki, Southland) early in March 2020, only a couple of hundred metres from the car-park, on the edge of the Taunoa Stream. The “grossular” part of its name is derived from the Latin word for gooseberry, because of the light-green colour of many hydrogrossular stones, like this one. White and brown are two other common colours, with other hues also known.
“H” is for “Hematite Jasper” – This is a small (3 cm long) hematite brecciated jasper stone found on Gemstone Beach, Southland, in February this year, tumble-polished in April.
Polished brecciated hematite jasper stone from Gemstone Beach.
Silvery-gray hematite.
The stone before polishing.
Jocelyn Thornton provides an example of a similar stone from the same beach (see photo below, left) on page 36 of her booklet “Gemstones” .
The following comes from my research to try to understand more about hematite jasper: Jasper is a dense opaque microcrystalline quartz (the crystals are too tiny to be seen by the naked eye). “Jasper” is derived from the Greek word for “spotted stone”, referring to its typical multicoloured, striped, spotted or flamed appearance. Jasper can form in many colours, not just the dark red we usually associate it with. Hematite is a common iron oxide compound widely found in rocks and soils. It occurs naturally in a variety of colours – black to silver-gray, brown to reddish-brown, and red colours. So it is often hematite that also causes the reds in jasper, including the segments of colour seen in brecciated jasper and the “moss” in moss jasper and the “bubbles” in orbicular/poppy jasper (www.quartzpage.de/jasper.html). Mindat has some great photos of jasper and hematite (see photo below, right).
However, it is the silver-gray hue present in jasper that we tend to call “hematite jasper”. The polishing of the stone I found brought out the silvery-gray hematite shine as well as some green (maybe epidote?). Hematite shows only a very feeble response to a magnetic field and is not noticeably attracted to a magnet.
For the next Post in this Alphabetical Series, see here. The Series Index is here.
This is the sixth Post on my June 2021 stone collecting trip to the South Island, and is also the 16th Post in the Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post on my June trip is the Sunday 6 June entry in this Post, and the first in the Facebook Group Series is here.
Monday 21 June 2021: Featuring eight stones from (what I thought was going to be) my last visit to Gemstone Beach this trip. Cold again but sunny and very little wind, good fossicking. Here are five of the stones:
Small dark red jasper.
One of the larger stones I collected.
Another banded argillite, nice and smooth.
Trace fossil stone with long continuous trace.
The Waimeamea River was blocked off by a build-up of stones during the last high tide so I could wander a kilometre further along the beach than previously. Here are the other three stones:
Breccia stone.
Quartz with tiny inclusions.
Near the Waimeamea River mouth, there sitting in front of me was a nice hydrogrossular garnet, one of the few I have found this trip.
It shone brightly among the other dry dull stones.
Waimeamea River blocked off from flowing to the sea. (Froth on the edge.) Walking across the stones to take this photo, I came across the hydrogrossular garnet in the previous photos.
Stones on Gemstone Beach today.
At the edge of the waves.
[Monday 21 June was also the day I made a Post in the Group’s Alphabetical Series – “H” is for “Hematite Jasper…”– see here.]
Tuesday 22 June 2021: Couldn’t resist the temptation to visit Gemstone Beach one more time before leaving tomorrow (despite scheduling today as clean-up and pack-up and load-up the car with stones). Bit of a cold breeze today but a big coat and hood did the trick. Found a few nice small-to-medium-sized hydrogrossular garnets (there have been very few up until today), and the usual colourful and interesting stones. Here are four of today’s finds:
Orbicular (poppy) jasper.
Here are another four of today’s finds:
Gemstone Beach scene today.
One of today’s hydrogrossular garnets.
Trace fossil stone, with iron staining.
And it’s finally farewell to Gemstone Beach for this fossicking trip.
Wednesday 23 June 2021 and Thursday 24 June: Travel days, no beach visits, no posts.
Friday 25 June 2021: Spent just over three hours on Kakanui’s Seadown Beach (North Otago) today. Among my finds were these beach agates and fossil sea floor stones:
Small beach agate #1, side A.
Small beach agate #1, side B.
Another small beach agate.
Fossil sea floor. These creamy-coloured stones often have tiny fossils in them.
Another fossil sea floor stone.
Fossil sea floor stone #3.
I think this is another fossil sea floor stone, slightly different in character.
I think this is also fossil sea floor, but dendritic (small mineral growths in it)
Maybe petrified wood, plus some jaspers:
Possibly petrified wood – wet.
Possibly petrified wood – dry.
Brecciated jasper.
Darker brecciated jasper.
Different coloured jasper.
Dark coloured jasper with a lot going on in it.
And some other stones from today:
Stone full of “entrances” or windows! Side A.
Stone full of “entrances” or windows! Side B.
Beach scenes from today near Kakanui:
Kakanui beach stones, from the southern end, in a small bay.
The beach near Kakanui when I arrived this morning.
Found this little guy just washed up by a wave.
The next Post in this Series is here, which is also the last Post on my June 2012 stone collecting trip to the South Island.
This is the fifth Post on my June 2021 stone collecting trip to the South Island, and is also the 15th Post in the Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post on my June trip is the Sunday 6 June entry in this Post, and the first in the Facebook Group Series is here.
Friday 18 June 2021: My second visit this trip to a beach near Slope Point (a 230 kilometres round trip from where I am based). Despite the cold day, Oliver Simpson agreed to accompany me. We went to a shaded beach again:
The stones on a shaded Slope Point beach.
The stones on a shaded Slope Point beach.
So I took the photos of today’s 10 selected stones afterwards, in the sun. Found a few interesting rhyolites and other stones. The first four:
I have now driven 2200 kms since leaving home (Whanganui) 15 days ago.
Saturday 19 June 2021: Today I did some reading and research about trace fossils, following up a link with “mokomoko”, went to try to see some on the other side of Invercargill, was unsuccessful, and did 30 minutes of fossicking at Riverton/Aparima. The photos start with five beach stones:
The Beach Past the Back Beach at Riverton/Aparima.
Banded argillite.
Trace fossils.
Now to move to some research literature. Geoff Chapple states in his book “Terrain: Travels Through a Deep Landscape” that Maori called the trace fossils of the south coast “mokomoko” (see the Post for Thursday 6 May) and I’ve been looking for more information on this. I bought a book online recently from Dead Souls Bookshop, Dunedin, on fossils in New Zealand (mainly to see if it had anything about fossil coral – it has some). At the end of the book is a map which includes a reference to Mokomoko Inlet and trace fossils. This may be a key link. But were the traces named after the Inlet or the Inlet after the traces? (I suspect the latter.) I decided to go and visit Mokomoko Inlet to see if I could find the trace fossils. Doing a quick internet search, I found an old geology journal article with more information: David Mossman & Lucy Force, “Permian fossils from the Greenhills group, Bluff, Southland, New Zealand” in the “New Zealand Journal of Geology and Geophysics” (1969). I drove to find the Inlet, but the side road to it was barred with a farmer’s fence so I turned around, nervous about intruding without discussing it first with the farmer.
The book bought from Dead Souls Bookshop. Published in 1990.
At the back of Hayward’s book.
The fossil localities in the 1969 article are located at the eastern end of the entrance to Mokomoko Inlet, where it connects to New River Estuary (Oreti River).
Trace fossils of Mokomoko Inlet. Page 669 in article.
More trace fossils of Mokomoko Inlet. Page 671 in article.
And the article refers to fossil coral – but that requires more research, maybe another tale for another day.
I will continue to do research and thinking about the trace fossils.
Sunday 20 June 2021: Foggy morning at Gemstone Beach today, but good fossicking.
Noon on a foggy winter Sunday at Gemstone Beach.
At the wave’s edge.
On the edge of Taunoa Stream.
Gemstone Beach stones.
Ten of the stones I found today, destined for tumble polishing:
This is the fourth Post on my June 2021 stone collecting trip to the South Island, and is also the 14th Post in the Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post on my June trip is the Sunday 6 June entry in this Post, and the first in the Facebook Group Series is here.
Tuesday 15 June 2021: Eight stones found during my fossicking at Riverton/Aparima today, at the Back Beach and Henderson’s Bay. It was a cloudy day – lack of wind meant a comfortable time on the beach despite the low temperature of 10 to 11 degrees.
Scenes from the Back Beach today:
The Back Beach, Riverton/Aparima, viewed from the east.
Stones on the Back Beach.
Back Beach, at the western end.
[Tuesday 15 June was also the day I made a Post in the Group’s Alphabetical Series – “G” is for “Green Hydrogrossular Garnet…”– see here.]
Wednesday 16 June 2021: Nine of the stones I found on Gemstone Beach today, to take home to tumble-polish.
Quartzite, with unusual white patches.
Unusual relatively-large inclusion in this small stone.
Too big to tumble, but will go in the “stone garden”.
The Taunoa Stream, near the carpark, was fordable today. But the Waimeamea River, 1500 metres west, was not – after being held back for a number of days by high banks of stones, it has broken through to the sea.
Gemstone Beach, looking towards the carpark, with the Taunoa Stream in-between.
Waimeamea River running diagonally across the beach to the sea.
Thursday 17 June 2021: One of the stones I came across today on Gemstone Beach is maybe Find-of-the-Trip, although the photos don’t do it justice:
Probably a jasper.
The massed piles of stones ran out at one point on the beach and I went over to walk through a few scattered stones near the edge of the waves… and there it was! Just in front of my left boot.
No missing this one! Very rare find.
Here are another seven stones selected for presentation today from a few hours spent on the beach looking for tumblestones.
Trace fossil stone – with quite small yet diverse traces.
Today’s segment of Gemstone Beach stones.
Looking towards the back of the beach, towards the cliff.
This is the third Post on my June 2021 stone collecting trip to the South Island, and is also the 13th Post in the Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post on my June trip is the Sunday 6 June entry in this Post, and the first in the Facebook Group Series is here.
Saturday 12 June 2021: Some of the stones I collected today near Slope Point (Southland). Many thanks to Oliver Simpson for hosting me again. The beach we visited was in shade and my photos were not as clear as usual, so no close-ups. NOTE – OCTOBER 2023 – Landowners are now refusing access to this beach, so please do not visit there without permission.
I was mainly looking for rhyolites, like this one.
Found by Oliver who kindly gave it to me.
Also found by Oliver and given to me.
A piece of black Southland petrified wood, to be added to the “stone garden” at home.
The beach near Slope Point.
Looking east.
Jaspers, quartzites, rhyolite, petrified wood, mudstone and many other kinds can be found here.
More stones on the beach.
However, right at end of the fossicking, we moved out of the shadows into the sun. I took photos in the sunlight of one of Oliver’s finds. He was interested in what the close-ups would reveal. It turned out to be a fascinating exercise.
Oliver’s stone. (He collects larger ones than I do.)
Close-up.
Even more detail.
Very close-up.
The other side of Oliver’s stone.
Sunday 13 June 2021: Seven stones found on Gemstone Beach this morning. It was raining so I didn’t use my camera on the beach – I took these photos later but the day was still wet and dull so the photos didn’t turn out as well as they could.
Small bright jasper.
Trace fossil stone. Quite bright traces on this one.
Amygdaloidal. Hard to get a clear photo.
Not sure what this one is. Some great tiny lines and waves.
I thought this was rhyolite but a closer look means I am not so sure.
Not the smoothest or shiniest, but nice pattern.
Amygdaloidal, I think. Again, not the clearest photo.
Monday 14 June 2021: Today’s fossicking was at McCracken’s Rest and Gemstone Beach. McCracken’s Rest is eight kilometres west of Gemstone Beach. Access to the beach from the road layby/lookout is not easy – I had to climb a fence and scramble down a slippery cliffside. Lots of stones on the beach, many quite large.
Photo taken this morning of Te Waewae Bay, from just east of Orepuki. Gemstone Beach is about a kilometre along the beach, McCracken’s Rest another 7 kilometres.
Looking back up at the McCracken’s Rest lookout from the beach. I climbed down the slope below it.
The lookout can just be seen top left. Lots of stones on the beach, many quite large.
Looking towards Pahia Hill from halfway down the slope below the lookout.
The stones on the beach below McCracken’s Rest.
Larger stones – I picked up about 8 red/reddish stones and grouped them around the central cream-coloured one for the photo. Far too big for a tumbler!
One of the sections of the beach dominated by larger stones.
However, there is not the diversity or quality of stones here that can be found at Gemstone Beach. The following are five of my most interesting finds found near McCracken’s Rest:
Trace fossils in argillite.
At Gemstone Beach, fossicking range was restricted by the Taunoa Stream being too high to ford. I wandered eastwards for a few hundred metres, an area usually clear of stones but with a few scattered there at present.
The Taunoa Stream, about 200 metres west of the carpark. Too high to ford today.
East of the carpark, a scattering of stones along the beach. Looking back towards the carpark.
The cliffs often slip, like this.
A stratum of well worn stones exists about 10 metres above the beach. Probably left by the sea long ago when sea levels were higher.
This brightly coloured layer sometimes emerges at the bottom of the cliffs.
“Mrs Purple” is a friend who has followed my stone collecting trips and sometimes indicated that she likes one of my purplish-coloured stones. She likes all things purple and I recently told her I would send her some polished purple stones. However, “purple” is not a straightforward colour when it comes to stones. This led me to take a closer look at the colour purple.
Only a tiny part of the electromagnetic radiation spectrum is visible to the human eye. Cosmic rays, x-rays, microwaves and radio waves, for example, are all invisible to us. Visible light is made up of a range of colours between red and violet.At school, I learned the sequence of the colours of the rainbow (which are the components of visible light) using the mnemonic ROY-G-BIV – Red, Orange, Yellow, Green, Blue, Indigo, Violet.
It was Isaac Newton in the 17th century who refracted sunlight through a prism to reveal the different wavelengths of visible light. The Blue-Indigo-Violet part of the spectrum is sometimes controversial as Indigo seems quite close to Blue. Some think that Newton wanted seven colours because of the traditional value put on the number seven (see medium.com). However, this Post is not about Indigo but about Purple, another name for Violet.
Traditionally, Purple is an equal mix of Blue and Red. However, Purple can also be viewed as a range of hues occurring between Blue and Red.
An added complication is that human perception of colour is not objective. We don’t all always see the same thing in the same way. We might be colour blind, for example. We also tend to see what we expect, based on our past experiences. Optical illusions demonstrate that what we see depends also on context, as in the following three colour illusions:
The human sense of sight is fallible, subject to tiredness and fading and such environmental conditions as light levels.
Now let’s turn our attention to stones. There are few purple stones, even fewer of which are the standard purple colour (though some variations of charoite and sugilite seem to be).Amethyst is a purple variety of quartz. According to mindat.com, it owes its colour mainly to gamma irradiation and the presence of iron – in fact, iron is the most common mineral to produce purple hues in rocks. Other minerals can have a purple effect. For example, purple sapphires have that colour due to traces of chromium present during formation – and they can range widely in hue.
I don’t come across beach stones of the standard purple colour in New Zealand. But there are a few that fall into some of these suggested 20 shades of purple.
In terms of the predominant colour of the “purple” stones I find on beaches, it is the darker hues like boysenberry, plum, sangria and mulberry that are more likely to crop up, for jaspers and quartzites, for example. But when one looks more closely at the veins within stones, where some mineral like iron has concentrated, then a greater range of hues emerge, including purple, violet, lavender and magenta.
As I noted above, human sight is subjective and fallible. What I see as purple may not be seen so by another. Light conditions affect how a stone looks. Photography adds another layer of complex variations and “distortions”. These should all be kept in mind when assessing the colour of a stone.
I sent 20 polished stones from three southern South Island beaches to Mrs Purple. They are among the “most purple” of the stones I have tumbled. Ten are from Gemstone Beach (Southland), six from Kakanui (North Otago) and four from Riverton (also in Southland). These are numbered in the three photos below.
Ten polished purple stones from Gemstone Beach.
Six polished purple stones from Kakanui.
Four polished purple stones from Riverton.
This Post, Part One of a two-part Series, will look at the ten stones from Gemstone Beach. I had originally intended to describe each stone in terms of which “shade of purple” can be found in it. But I discovered that this was too difficult, moving between the shades and the stone, trying to distinguish the hues. I felt I ended up giving inaccurate attributions. So I will restrict myself to more simplistic observations, letting the photos of the stones largely speak for themselves. For each stone, a photo of each side is presented, along with a close-up from each side. Here are the first two stones from Gemstone Beach:
Stone 1
Stone 1
Stone 2
Stone 2
Most of Stone One is a mix of darker hues and small areas of lighter hues as well as white quartz crystals. There is an intense wavy band of what appears to me to be “magenta” in colour. Stone Two is a contrast to Stone One, being much lighter in colour overall, having hues that are much pinker. Stones Three and Four are different again:
Stone 3
Stone 3
Stone 4
Stone 4
Stone Three again has light to dark hued spots all mixed in together though they are much finer-grained than in Stone One. Stone Four is a dark reddish-purplehematite jasper (the gray hematite is an iron oxide). Stones Five and Six are the smallest of the 20 stones for Mrs Purple:
Stone 5
Stone 5
Stone 6
Stone 6
Stone Five, a small jasper, has some cream-coloured sections along with at least two different dark hues of purple and a more reddish band. Stone Six is amygdaloidal – a volcanic stone that has had small vesicles (holes) in it caused by gases, which were then filled by mainly (in this case) white material left behind as water has passed through over thousands of years. There are three darker shades of purple apparent as well. Stones Seven and Eight are just a little larger:
Stone 7
Stone 7
Stone 8
Stone 8
Stone Seven has an almost orange-purple through it, while Stone Eight has intense dark purple veins. Stones Nine and Ten are larger, with Stone Ten being the largest of the Gemstone Beach stones:
Stone 9
Stone 9
Stone 10
Stone 10
Stone Nine, with a clear silica vein, has a scattering of light purple throughout it. Stone Ten is predominantly a dark stone, with some thin veins of intense purple and some creamy-white patches.
Part Two of this Series (not yet available) looks at the remaining ten stones sent to Mrs Purple, from Kakanui and Riverton.
While writing this, I viewed a tv documentary on the New Zealand music band Six60, “Till the Lights Go Out”, and became aware of their song “Purple”:
“Purple” by Six60
I’ve been holding on to nothing Reaching out to something Waiting for someone like you If only there was one thing Some way of controlling All these other things I do
Shock me girl electric blue Standing while the wreck’s still true And so we fall And through it all I’m left here with this purple heart of mine Battle’s won The war is done And the sky is purple, purple, purple
Last night I was dreaming Falling from the ceiling Woke up just before the sound And it got me thinking Oh I got that feeling We’d already hit the ground
Shock me girl electric blue Standing while the wreck’s still true And so we fall And through it all I’m left here with this purple heart of mine Battle’s won The war is done And the sky is purple, purple, purple
This is the second Post on my June 2021 stone collecting trip to the South Island.This is also the 12th Post in the Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.
Tuesday 8 June 2021: Seven stones found on Seadown Beach, a Kakanui Beach (North Otago), this morning – in the sequence in which they were discovered. I picked up many more but these were among the most interesting ones. The first four stones:
Looking back towards the low morning sun, at the southern end of the beach, where I began my fossicking.
One of the first stones I found – could be orbicular jasper.
Nice little pale green quartzite.
I picked this small stone up because I like the “black dots” effect. It was only upon examining the photos more closely that its intricacies revealed themselves…
There are some gorgeous jaspers on this beach. I left a number behind, but couldn’t resist this one.
When I started off, the temperature was about 3 degrees but it was sunny with little wind. I tried hard not to pick up too many as I am still on my way south to Riverton and Gemstone Beach (Orepuki). The last three stones:
The last photo I took on the beach before departing.
There are lots of gorgeous yellow quartzites (and their variations) on this beach, and I worked hard to be selective. I decided to pocket this one because it is unusual to see the darker markings.
I could not leave behind this gorgeous small yellow quartzite. One of my top finds of the morning.
I was attracted by the green markings on this stone. It was only when examining the photos that I realised this too is a quartzite.
Wednesday 9 June 2021: This is the day I made a Post in the Group’s Alphabetical Series – “F” is for “Fossil Worm Casts” – see here.
Thursday 10 June 2021: Ten stones selected from my first visit this month to Gemstone Beach (Orepuki, Southland). The first five:
Gemstone Beach today.
Great patterning.
Small stone.
Another small stone.
A lot of the stones I found had interesting tiny inclusions or crystals.
I walked this afternoon from the carpark westwards to the mouth of the Waimeamea River and back, spending three hours on the beach. The last five stones:
Amygdaloidal stone.
Gorgeous small green quartzite.
The only hydrogrossular garnet I found.
Fossil worm cast stone – argillite.
Porphyritic stone. Too big to tumble polish, so left it there. 20 metres later I changed my mind and went back and put it in my backpack. It will go in the “stone garden” back home in Whanganui.
Friday 11 June 2021: Seven of the stones collected today on Gemstone Beach (Orepuki, Southland). The first four:
Amygdaloidal.
Small stone.
Another small stone.
There is a great diversity of colours and patterns in these stones. The last three:
Probably banded argillite.
Probably breccia.
The view from the carpark, looking southeast towards Pahia Hill.
Stones in a small stream that runs across Gemstone Beach.
This is the eleventh Post in this Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.
Saturday 5 June 2021: Tumble-polished stone found on Birdlings Flat sometime over the last couple of years.
Other side of stone.
Sunday 6 June 2021: Three finds from my time on a beach just south of Timaru this morning. I am on my way south again to restock my beach stones for tumble polishing. My very first visit to this beach was yesterday, I just had to go back today, as there are some beautiful quartzites there. I also saw three seals. Right at the end, I came across a tiny fish (about 4 cms long) gasping for breath a couple of metres up the beach from the waveline – I carefully returned it to the sea.
I found a few green quartzites.
I’m hoping I can tumble this one in my 12lb barrel.
The beach just south of Timaru. I suspect recent stormy days have piled up more stones than usual – or at least given them a big stir.
The tiny fish I returned to the sea.
Monday 7 June 2021: Five small stones from my visit this morning to a beach near Moeraki Village, North Otago. Close inspection of each revealed fascinating details. Most are chalcedony (agate). The first three stones:
Stone 1 – small agate with “fortifications”.
Stone 1 held up to the light.
Stone 2 – orbicular chalcedony?
Stone 3 – another small agate.
It was difficult to see the details of these small stones before working with the photos. On the beach, I could often just see a hint of something interesting going on. Here is a photo of the beach, followed by photos of the other two stones:
The small beach near Moeraki Village.
Stone 4 – likely also to be chalcedony of some kind, maybe dendritic.
A 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 “A” and “B” can be found here. The following are my Posts for “E” and “F”.
“E” is for “Entrance” – This is the opposite of “Eye”. An “eye” in a stone “looks outwards” and is often opaque. An “entrance” allows you to “look into” a stone, to see beyond its surface. “Entrances” can be translucent veins or crystals or druzies or holes or cracks. This tumble-polished stone, 6.5 cms long and 3.5 cms wide, comes from a Kakanui beach. There are many small clear “entrances” to it, maybe vesicles filled over time as water moved through them. Your eye is drawn to look inside the stone.
Other side of stone.
“F” is for “Fossil Worm Casts” – This is the term used locally for trace fossil stones found at Gemstone Beach in Southland (I have also found the same stones elsewhere in Southland and around Whanganui). I found this stone on Gemstone Beach in February this year. A no-longer-in-place Heritage Trail sign refers to these stones as “Fossil Worm Casts”. The Riverton Museum Te Hikoi has a couple on display, labelled “Worm Trace Fossils”. Te Ara, The Encyclopedia of NZ refers to a “worm-like impression…, traces left by a worm burrowing through mud”.
A geologist I consulted said that these trace fossils were most likely left in argillite rock over 250 million years ago, in the Permian Era, by an animal burrowing within the ancient sea floor. There is a great diversity of trace shapes to be found in these stones, along with variations in size and colour. But you can see how similar they often are to contemporary earthworms and their casts. However, the animals that left these traces could have been quite different. Furthermore, the traces could be “casts” of animals that have dissolved during the petrification process, their bodies being replaced by other material.Which would mean they are not trace fossils… Continued thought and research are required.
For the next Post in this Alphabetical Series, see here. The Series Index is here.
This is the tenth Post in this Series of my recent regular Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post in this Series is here.
Tuesday 1 June 2021: Kakanui beach stone, polished, used in aquarium. I found this stone earlier this year. I can’t make up my mind whether it is a jasper or quartzite. I tended towards quartzite until I polished it – it came out of the tumbler with the kind of little rough patches that a jasper often has. It’s the kind of stone that could be put back to 400 grit and smoothed more before polishing again – it’s big enough to take this treatment and remain a good size.
Kakanui stone after tumble polishing.
Other side of stone.
But I decided instead to put it in the new aquarium we recently bought. The fish haven’t arrived yet but their aquatic environment is nearly ready for them.
The new aquarium being prepared for the fish. The Kakanui stone is at lower left – circled in next photo.
A closer view.
Wednesday 2 June 2021: This is the day I made a Post in the Group’s Alphabetical Series – “E” is for “Entrance” – see here.
Thursday 3 June 2021: Birdlings Flat stone, probably a quartzite, came out of the polish barrel yesterday. Two sides, two different colours. Full of “entrances” that invite the eye to see inside.
Birdlings Flat polished quartzite.
The reddish-brown side.
The cream-coloured side.
Friday 4 June 2021: This stone was found on Gemstone Beach by my sister Helen. I finished tumbling it for her three days ago.
