In this Series, I present 30 recently polished stones from Gemstone Beach/Te Waewae Bay. They illustrate the great diversity and beauty of the pretty stones of this beach, as well as some of the challenges a tumble polisher faces to obtain a completely smooth and well-polished stone (if that’s their aim). These 30 stones were selected from the smaller stones from batches tumbled in two 3lb barrels. Part 1 described Stones 1 to 5, with the following Parts dealing with another five stones each. The five stones featured here are the final five, and are the smallest of the 30.
Stone 26 caught my eye because of the small light patches on a mainly black stone.
It could be an amygdaloidal stone, like Stone 13, or a breccia, like Stones 1 and 2, or it could be a stone consisting of a variety of crystals – it’s difficult for me to be sure. It can be hard to get a good consistent polish on a stone like Stone 26 because of the variety of minerals in it, some of which might polish well and others of which may not. The close-ups a less than perfect surface, with lots of tiny blemishes.
It was the white quartz vein in Stone 27 that caught my eye on the beach on 30 April 2023 – it is the last stone in this Post. But the bands of hues of green are also attractive.
I was disappointed the stone did not finish its tumble-polish with a clearer surface.
Stone 28 is a small thulite pebble, with this type of stone’s distinctive pink. It was found on 18 March 2024.
Thulite is the national gemstone of Norway where it was first discovered. As Wikipedia notes, it is manganese that is the source of the pink colour. A thulite stone was January 2022, Stone of the Day #5, and that Post includes a photo of specimens from the Riverton Aparima Museum. Three thulite stones from Gemstone Beach appear in this Post (Stones W69, W70 & W71).
Thulite stones are usually very attractive and often have areas of swirling pink. However, some of them fail to tumble polish well, not taking a shine at all, and sometimes the material making up the stone can be a little crumbly. Stone 28 has a number of small rough areas attesting to these problems. Overall, it is a disappointing outcome.
In contrast, Stone 29 has tumbled very well, especially Side A. This is a variety of orbicular or poppy jasper with hematite (Stones 16 and 20 are also hematite jaspers, but not orbicular).
The orbs are not as well formed as in these two otherwise very similar stones, September 2021’s “O is for Opaque Orepuki Orbicular Jasper” and January 2022 Stone of the Day #4. Further poppy jaspers feature in this Post and this Post. Orbicular jasper is a variety of jasper which contains orbs or spherical features. Mindat states it is “a highly silicified rhyolite or tuff that has quartz and feldspar crystallized into radial aggregates of needle-like crystals forming orbicular (spherical) structures”. There are some white blemishes at the bottom right of Side B which look like tiny flakes of something – not sure whether they are remnants of the polish or, probably more likely, of some mineral like mica. Apart from these, Stone 29 has turned out very smooth and clear, largely due, I think, to the suitability of hematite jasper for tumbling.
Finally, Stone 30 is a very fine-grained light green stone with white shapes in it.
It has tumbled smoothly though has not taken a significant shine. I’m tempted to guess that it is a mudstone, such as argillite, with maybe epidote turning parts of it green. The white shapes do look like milky quartz crystals in colour but they lack sharply defined boundaries that usually come with such.
This brings this Series to an end, exposing the flaws in polished stones that can become apparent under close scrutiny. It provides a balance to those many Posts that often show gorgeous well-polished stones or unpolished wet stones where the water fills in and hides tiny scratches and holes.
The first Post in this Series is here.
