We had some more wind and rain yesterday (Wednesday) then the sun returned though the temperature was still low. At noon I visited Papatotara Beach for 90 minutes at low tide, the temperature being eight degrees. It was very wet and muddy at the bottom of the track down to the beach so I was glad for my sturdy pair of gumboots. There were fewer stones and more sand at the waves’ edge due to the low tide, leading to a less productive fossick. However, my 17 finds included some interesting specimens, as revealed by the photos of the six featured below.
My most interesting find was what I think is a small brecciated argillite:
Tectonic stress has most likely fragmented the middle of the stone, then hot water running through has deposited quartz to fill the gaps and hold the fragments in place.
I picked up this little stone because of its dark red halo of iron oxide and I could spot some very tiny patches of colour in it. The photos reveal that it is a breccia though maybe the fragments are small enough for it to be classified as a sandstone:
A stone with interesting white veins:
I suspect the veins are quartz, but I am unsure.
Two contrasting black and white igneous stones – one dominated by white, the other dominated by black:
See Section 5 “Stones With Opaque White Crystals” in this Post for an idea of the fuller range of such stones.
Finally, yet another intriguing small jasper I have found this trip:
On Saturday I take part in the Open Day of the Southland Geological and Lapidary Club, giving away some polished Gemstone Beach stones (especially trace fossils, rhyolite and hydrogrossular garnets).
The next Post is about the “Mini Rock and Mineral Show/Open Day” organised by the Southland Geological and Lapidary Club in Invercargill. An Index to the Series is available here.
