The stones of the Back Beach, Riverton.
The cliffs to the left of the carpark. Stones in the foreground.
The lagoon of the Waimeamea River, created by the piling up of stones on the right, preventing the river from reaching the sea, though it seeps through the stones. The lagoon is twice the size I have previously seen.
Seagulls at Gemstone Beach
The snow-capped mountains of Eastern Fiordland, from Gemstone Beach. A wild sea generated some powerful waves.
The kind of small stone that will likely look stunning after polishing.
Delicate veins.
Gorgeous colours. This stone was too big to tumble polish so I left it on the beach.
A stunning stone, probably a quartzite.
As mentioned in the first Post of this Series, I am undertaking a three-week stone collecting trip to the South Island by car. I am posting up-dates on Facebook for family and friends, then re-posting them here.
Day Six, Gore to Riverton, Visit to Back Beach – A cold but sunny day in the south! Arrived at Riverton at lunchtime. Visited the Back Beach for about 45 minutes as the late afternoon sun was going down. Were a few people there, enjoying the end of the first long weekend under Alert Level Two.
The stones of the Back Beach, Riverton.
The end of the road at the Back Beach, a popular place for holiday-makers.
The kind of small stone that will likely look stunning after polishing.
Made interesting by the yellow veins.
Likely to be argillite, a mudstone.
Probably petrified wood.
The grey material looks porous and not likely to polish. Will tumble this one and see what happens.
Could be interesting.
Will polish well.
A lot of small fragments compressed together?
The stones on the Back Beach are a very mixed bunch. Most are rough and don’t look good candidates for polishing. However, I have often been surprised at how well they turn out after spending time in the tumbler barrel. The key is to see the potential of the colours and patterns. I found very few fossil worm cast stones despite them having been much easier to find earlier this year.
Looking from the Back Beach across a calm Foveaux Strait to Rakiura/Stewart Island.
Small banded ignimbrite.
Small chipped fossil worm cast stone.
Fossil worm cast stone.
Fossil worm cast stone.
Day Seven, First Visit to Gemstone Beach – Warmish cloudy day, spent three hours on Gemstone Beach with my sister Helen. About 10 other people were on the beach at different times as well, one was a local collector of hydrogrossular garnets I had met before, and three were Czech people stranded in NZ by the Covid-19 pandemic, undertaking a South Island tour in Level Two. Helen and I first went to the left of the carpark where stones are not usually deposited on the beach. Today there was a good selection there.
Looking to the left from the carpark – there were two or three large drifts of stones along the beach here, which is unusual.
The cliffs to the left of the carpark. Stones in the foreground.
Panaroma of the Taunoa Stream which is to the right of the carpark. There is a small lagoon here now when on previous visits there was just a stream running into the sea. The figure to the left of centre is my sister Helen.
Delicate veins.
A complex small stone.
Quartzite-type stone.
Small green and white stone.
Very interesting inclusions in small dark stone.
We then dropped our initial finds off in the car before walking to the right, past the Taunoa Stream. About 500 metres in that direction we started to find a few small hydrogrossular garnets. Overall, many interesting stones on the beach.
Gorgeous green quartzite.
Gorgeous colours. This stone was too big to tumble polish so I left it on the beach.
White hydrogrossular garnet, one of the bigger ones I found, though it is still small.
Hydrogrossular garnet – quite a thin slice-like piece.
Fossil worm cast stone with unusually dark traces.
Probably petrified wood.
Brecciated stone.
Small black and white stone.
Day Eight, Second Visit to Gemstone Beach – Another warm day, spent four hours on Gemstone Beach with my sister Helen. We timed our arrival for just after high tide and decided to move westwards along the beach towards the Waimeamea River mouth, just over one kilometre away. However, we were initially unable to cross the Taunoa Stream so spent 30 minutes or so on the beach near the carpark until the tide went out a bit more and the Taunoa Stream went down. We then made our way towards the Waimeamea River, arriving there about two and a half hours later, collecting stones all the way.
The Taunoa Stream upon our arrival. At the top, the waves are bringing in water (white foam) which is keeping the water level high and keeping the outflow (lower flow) strong. Once the tide receded a bit more, the outflow reduced in size so we could cross.
The lagoon of the Waimeamea River, created by the piling up of stones on the right, preventing the river from reaching the sea, though it seeps through the stones. The lagoon is twice the size I have previously seen.
One of about 6 or 7 seepages from the lagoon. Eventually, as the stones are washed away, a channel can be formed for the Waimeamea River to discharge directly into the sea, until the tide comes in and piles up stones here again.
Tumble polishing should make this even more interesting.
A stunning stone, probably a quartzite.
An unusual clay-like colour as a fine matrix to pieces of quartz and some silica veins.
A stone made up of tiny fragments, in a yellow wash.
Rhyolite, a volcanic rock.
Great range of greens here.
Another hour saw us back at the carpark, just as a cooler breeze was getting up. We found a few hydrogrossular garnets, as well as some nice specimens of fossil worm cast stones, along with a good number of colourful and interesting patterned stones likely to respond well to tumble polishing.
Gemstone Beach stones of the size that is common for most of the beach.
Some of the larger Gemstone Beach stones that appear as you move closer to the Waimeamea River mouth, though smaller ones continue to predominate.
Nice small grey hydrogrossular garnet with some yellow at bottom.
Small hydrogrossular garnet.
Tan coloured hydrogrossular garnet. garnet.
This doesn’t look like a hydrogrossular garnet but I have seen it grouped with the other type in the Riverton Museum and seen references to a chalk-like variety.
Similar to previous photo but more smooth and with a pink blush. I refer to these as a “porcelain-type” hydrogrossular garnet because of its fine white character.
Fossil worm cast stone. The trace rising from the bottom left is chevron-shaped, known as ichnogenus Protovirgularia, a general term for the trace fossil shape irrespective of its size and what may have produced it.
Similar shape trace fossil, different type of stone and colour.
An elongated ichnogenus Protovirgularia.
Spot the ichnogenus Protovirgularia… There are three or four here.
Fossil worm trails emerging out of the stone.
A large specimen of a quartzite-type rock. I left it on the beach as it is far too big to tumble polish.
Day Nine – Too wet and windy, stayed inside.
Day Ten, Third Visit to Gemstone Beach – A cold front moved through yesterday and the temperature has dropped. However, I dressed warmly and headed to the beach. Ended up spending five hours there. Arrived just before high tide, and the waves were high and powerful, forcing me initially to look for stones at the foot of the cliff at the back of the beach.
The snow-capped mountains of Eastern Fiordland, photo taken from just outside Orepuki.
The snow-capped mountains of Eastern Fiordland, from Gemstone Beach. A wild sea generated some powerful waves.
The occasional wave lapping over the stone bank at Waimeamea River mouth/lagoon.
On my way up the beach, westwards, I kept close to the cliffs, the safest place to be. The stones were wet as they were in the shade, so fossicking was good.
On this little ledge of stones, I found a couple of interesting stones…
This is the first I found on the ledge.
Close-up of previous stone.
And a little further along the ledge was this larger stone…
It has some great fossil worm casts. It is too big to tumble polish but I decided to take it home as an excellent example of such trace fossils.
A different type of fossil worm cast stone.
Close-up of fossil worm casts on previous stone.
A small lumpy stone found on my way back, 250 metres from the car park. I am fairly certain that the lumps are fossil worm casts.
Making the lumps (fossil casts) more visible by manipulating the image.
I went about one kilometre past the Waimeamea River mouth, further than I have gone before. I dropped off a couple of stashes of stones along the way to pick up when returning, so my backpack would remain as light as long as possible, though by the time I got back to the carpark it was quite heavy!
The bright colour of this stone grabbed my attention.
A more subdued colour…
Close-up of previous stone.
A closer inspection reveals the complex character of this stone…
Close-up view of previous stone.
Part of the beach where sand predominates along with driftwood. There, I found…
…this interesting stone.
It is a banded argillite.
Maybe reminiscent of the planet Jupiter.
Silica veins are always interesting.
A thicker vein.
See here for the next Post in this Series.
Author: tumblestoneblog
Retired Academic, male, living in the New Zealand countryside near Whanganui with his wife as well as Jasper the dog, Fluffy the cat, Dancer and Penny, the horses, and a shed half-full of stones. Email john.tumblestone@gmail.com.
View all posts by tumblestoneblog
5 thoughts on “South Island Stone Collecting Trip, May/June 2020 – Days Six to Ten”