Oliver Simpson found this stone on a beach near Moeraki Village in North Otago, just a few kilometres from the well-known Moeraki boulders. The stone is probably chalcedony with a white frosted outer layer, likely caused by weathering. One side of it seems to have a thicker layer of white than the other.
Oliver and I discussed if we should try tumble polishing the stone to see what was beneath the white. We both liked the white skin and I was skeptical whether tumbling would “improve” it. But Oliver thought it was worth a go, so I took it home and tumbled it for him. I was floored when I saw the results of the first 400 grit tumble! One side was still predominantly white but the other was a revelation, revealing the inside structure of the stone.
After consultation with Oliver, I put the stone through another week’s tumble in 400 grit. Not a lot of change occurred, and we discussed whether to try to remove more of the outer layer. We decided that the odd white speck on the “A” side was ok. I went on to polish the stone, before sending it back to Oliver in the mail.
The final polish did not add a lot – the most significant changes occurred with the initial 400 grit tumble. The end product shows, on one side (Side A), what is inside the stone, which also turns out to be translucent.
The other side (Side B) retained some of the original interesting weathering and its patterns.
