FB Group Posts: 29, 30 & 31 May 2021 – Gemstone Beach Purple Stone, Slope Point Petrified Wood, and a Slope Point Mystery

This is the ninth 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 29 May 2021: A stone for “Mrs Purple” – This is a recently tumble-polished stone found on Gemstone Beach (Orepuki, Southland) earlier this year, 4.5 cms long, has polished very well. It’s predominantly a dark stone, with some thin veins of intense purple and some creamy-white patches. I have a friend known as “Mrs Purple” who loves all kinds of things of that colour – I promised her I would send her some purple stones collected down south, so this one will soon go to her (see this Post for Mrs Purple’s stones).

Sunday 30 May 2021: Small three-sided stone of petrified wood, found at Slope Point on 3 March, finished tumble polishing on 19 May, 2.5 cms long. Most petrified wood in this area is black, this is an exception and stood out on the beach because of the light brown colour, showing the grain. It polished very well, with just one shallow indent on one side (left there because of the small size of the stone).

Monday 31 May 2021: This small Slope Point stone came out of the tumble polisher with mixed results. Patches are very shiny but other parts are rough. There are still cracks on the surface. Looking carefully at photos of it led me to appreciate a number of aspects of the stone. When I found it on the beach, I thought it might be some kind of sandstone, or maybe even petrified wood. Given the grain patterns and textures revealed by the photos, I now wonder if it is petrified plant material of some other kind. An interesting mystery to me. [One Group member suggested that maybe this is petrified bone, another thought it could be petrified palm.]

The next Post in this Series is here.

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

The first Post in this Series is here.

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

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

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

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

Petrified wood:

Finally, a few more Slope Point beach pebbles:

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

Here’s six of my interesting finds:

Another five interesting finds:

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

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

Stay-at-Home Day Thirteen, Tuesday 7 April 2020: Stone Thirteen

Stone Thirteen was found on Gemstone Beach last year and came out of the final polish tumbler in the week-end. The presence of a grain-like pattern in the stone, and its slight brittleness, means that it is probably petrified wood.

Petrified wood forms when a tree or piece of wood is buried by sediment and protected from decay from oxygen and biological organisms. Then groundwater, rich in dissolved solids, flows through the sediment and replaces the original wood material with a mineral such as silica, calcite, or pyrite, or another inorganic material such as opal.

The next Post in this Series is Stay-at-Home Day Fourteen, Wednesday 8 April 2020: Stone Fourteen.

Another Visit to Birdlings Flat, Late June 2016 – Part Two: Birdlings Flat Gemstone Museum Again

The second day of our visit to Birdlings Flat, Petra and I visited Vince and Colleen Burke’s Gemstone and Fossil Museum on Hillview Road. This time, Colleen opened up the Museum for us and we got to talk with her about Birdlings Flat and the stones in the collection. Vince then took over from her after about 15-20 minutes. Petra bought a good-sized batch of agatised wood which we will have a go at polishing sometime. Vince generously gave her three pieces of polished agatised wood, to give her an idea of the end product of polishing.  Agatised wood is a form of petrified wood and is in effect a fossil. It forms when plant material is buried by sediment and thus protected from the decaying action of oxygen and organisms. Groundwater rich in dissolved solids flows through the sediment replacing the original plant material with minerals such as silica, calcite and pyrite or another inorganic material such as opal. The result is a fossil of the original woody material that often shows preserved details of the bark, wood and cellular structures. “Agatised” wood is wood that has been replaced by agate, a form of chalcedony or microcrystalline quartz.

After about 30 to 40 minutes at the Museum, we moved onto the beach and spent nearly three hours fossicking for stones, walking eastwards right up to the end of the beach where it butts up against Banks Peninsula. We collected a few kilograms of stones, and returned the next day to collect even more. The next post will look in more detail at the variety of these stones.  

My Visit to Birdlings Flat, Day 2: Stone Collecting

I bought some stones from Vince Burke at the Gemstones and Fossil Museum. I normally only like to collect what I find but there are special exceptions – and the Museum is a special place. Vince threw in some extras as well, so I came away with two rock agates from the Woolshed Creek area near Mt Somers, three large agate stones from Birdlings Flat, and some petrified and agatised wood from the Hororata River area. 

But my main purpose that day was to find stones of my own that I could polish. So after I had visited the Gemstone and Fossil Museum, I spent about 2 1/2 hours on the beach, concentrating my time on the northern end, walking all the way to the cliffs. The wind was much stronger, but down near the waves was the lowest part of the beach and somewhat sheltered from the north-wester. There were slightly more people around this day than the previous one – mainly fishing and, like me, hunting for stones.

I chatted with three people. Charles came from Christchurch and had been interested in stone collecting for just a couple of months – he had a friend who polished stones but did not himself have a tumbler. Charles was nearing retirement age, like myself. He explained to me that he was mainly looking for agate stones – he gave me some he had found. I had not developed the eye to find them as they are rather plain looking and I tend to seek out colour. As we talked, Charles said, “Oh look, there’s one!” and he stepped a metre away to pick up a small agate. And a minute later, he spotted another one not far away.

Later I ran into a woman who I found out was the daughter of Vince Burke, the Museum man. She was also out looking for agates and generously gave me a handful. Later still, I encountered a local on his afternoon walk who told me a bit about the beach and its dangers. “It’s a killer beach”, he said. The waves can be treacherous, coming in further and more quickly than one anticipates – turn your back on them to your peril. And it gets deep quickly off shore – people who go in after their dog can get into trouble. He also gave me a few agates he had collected that afternoon. 

I reached the cliffs at the north end of the beach but did not linger there. Charles had explained that one of the Christchurch area earthquakes had brought down part of the cliff-face. I had experienced a small but distinctly-felt earth tremor the night before in Christchurch and I was uneasy to focus too long on the stones at my feet when a mass of over-hanging cliff loomed above. 

I collected somewhere between five and six kilograms of stones that day, to add to the eight kilograms from Day One. That evening I packed them carefully into both my cabin baggage and checked baggage for my flight the next day back to Hamilton. Heavy bags!

My Visit to Birdlings Flat, Day 2: Gemstone and Fossil Museum

On my first day at Birdlings, I had seen the sign for the Museum so decided to visit it at the start of Day 2 of my visit. I had seen references to it online, where it was described as a private rock collection open to the viewing public.  One community information site added: “The display is mostly Canterbury material gathered from the rivers and hills, agate, quartzite, jasper, petrified woods etc, of which after many years would have all ended up on the beach at Birdlings Flat.” Another site stated:  “The Gemstone and Fossil Museum was opened in February 2003 by Vince and Colleen Burke and their children, who collected the many kinds of gemstones off Birdlings Flat Beach over 34 years. The collection has grown to include fossils collected since 2002, mostly from Amberley Beach to Kaikoura.” Vince is quoted in a 2012 North & South article on the Little River area as saying, “My wife wanted me to get everything out of the lounge” when they decided to live permanently at Birdlings Flat, sometime after his retirement as a builder in 2003.

The Museum is located at the end of Hillview Road at Birdlings Flat, a narrow road crowded on both sides by holiday homes and residences. Going in the gate, I found myself in a large courtyard to the left of which was the Museum building. A sign said to blow the horn on the wall, so I did, and Vince appeared and opened up. Inside is possibly the best laid-out and presented display of rocks and fossils that I have ever seen, a testament not only to the Burke family’s passion for stones and fossils but also to Vince’s intelligent ordering and labeling of the material being presented.

My favourite corner contained the petrified wood, agates and quartzites.

Petrified wood:

Agate stones:

Quartzite and rhodonite:

Perhaps more than half of the displays are of large colourful agates, most of them found by Vince himself in different parts of Canterbury:

One wall has a display of agates and rocks from different parts of New Zealand. Entry to the Museum is free, though donations are welcome, and you can purchase your own stones, rough or polished, to take away with you:

Vince graciously showed me around and shared some of the stories associated with various stones, especially the large colourful agates. He helped me to identify some of the stones I had been collecting recently. I bought some petrified wood and agate stones on the way out, and Vince then showed me around his workshop which contains his large homemade tumblers, vibratory vats, and cutting saws. All in all, an overwhelming and amazing experience.

Birdlings Flat Gemstone and Fossil Museum is open every day, 9.30 am to 5 pm, except when Vince is away rockhounding.  

See also “Another Visit to Birdlings Flat, Late June 2016 – Part Two: Birdlings Flat Gemstone Museum Again”.