Seven Stones for a Fellow Fossicker

I recently sent seven polished stones to a fellow fossicker in Taranaki who expressed an interest in some of the stones she had seen featured on this Blog. All of the stones were chosen by me partly because of how they feel, being able to act as touch stones. An interest had also been expressed in Slope Point stones, so the first four come from Slope Point, with Stone 5 from Birdlings Flat, Stone 6 from Gemstone Beach and Stone 7 from Kakanui.

Photos of both sides of each stone are presented below. Two close-ups are featured for each side – like shining a torch on the stone and looking at it with a magnifying glass of two different strengths.

Stone 1 is a Slope Point breccia. Beccia is where small sharp fragments of stone are cemented together in a fine-grained matrix. In this stone, the fragments are of varying sizes and composition.

Other examples of Slope Point breccia can be found at the end of this Post. A description of breccia, partly in relation to Gemstone Beach stones, is presented in this Post.

Stone 2 is also from Slope Point, maybe of volcanic origin, maybe rhyolite.

Another Slope Point rhyolite, Stone 3 is perhaps thee most spectacular of the seven stones when viewed in close-up. The tiny features and structures are complex.

Another Slope Point stone with similar complexity can be found here.

Stone 4 is a darker stone from Slope Point, likely to be volcanic in origin as small crystals can be seen within it. The red colouring will be from iron oxide.

Travelling now to a different part of New Zealand, at Birdlings Flat in mid-Canterbury I once found this white-grey quartzite (reconstituted quartz sand), Stone 5. I find the gradations of colour very interesting in such stones, and they tend to tumble polish very well.

For similar grey quartzites from Birdlings Flat, see the entry for Friday 7 May 2021 in this Post.

Stone 6 is one of the types of stones that can be found along the Te Waewae Bay coast of Southland, across from Rakiua/Stewart Island. It’s a banded argillite, a mudstone showing strata of seafloor sediment, and was found at Gemstone Beach.

There’s a green version of banded argillite in this Post and a brown version here.

The final stone comes from Kakanui’s Seadown Beach, just south of Oamaru in North Otago. Like Stone 5, it is a quartzite, though of a different colour. This colour is very common on Seadown Beach, and stones of this shape can be found occasionally. Tiny clear pieces of quartz can just be seen in the stone in the most magnified close-ups.

More information on Kakanui quartzites can be found here and the entry for Wednesday 26 May 2021 in this Post.