I found this small dark-coloured stone on a Slope Point beach in Southland sometime in 2021 – I didn’t take a photo of it at the time as it was much less interesting than many of the Slope Point stones I collect.
However, some faint marks and lines hinted at possibilities, and these have been brought out well by polishing. It was tumbled with a number of other Slope Point stones (including Stone #3), initially in 400 grit for just over a week, then spent 10 days in tin oxide pro-polish, and four days in borax as a final burnish. It finished the tumble-polishing process at the end of August in 2021.
There are lots of little interesting areas in Stone #6, no doubt related to its volcanic origins. They include the occasional isolated tiny square or oblong (cubic?) crystals that can be seen in the photos above and below.
Some research on the internet has brought up pictures of stones with pyrite crystals that look very similar (e.g. geology.com):
Stone #7 is probably rhyolite. It is 4 cms long and rounded, so that a third side can be photographed, revealing further intriguing details:
Stone of the Day #8 is here. The Index to the January 2022 Stone of the Day Series is here.
2 thoughts on “January 2022, Stone of the Day #7 – Another Volcanic Stone from a Slope Point Beach”