Dark red jasper is a reasonably common stone on many beaches of the South Island of New Zealand. I have picked up many such stones at Riverton and from Gemstone Beach and Birdlings Flat. This one comes from Birdlings Flat, was collected from there in 2019 and finished the polishing process in March this year.
In my experience, it is difficult to achieve a high polish with jasper using tumbling with tin oxide polish powder. The stones seem to retain some dullness. In his book, “Modern Rock Tumbling” (2008), Steve Hart states that cerium oxide is “the polish of choice” (page 60) for jasper. I managed to obtain a small amount of cerium oxide a couple of years ago and used it only once, having not yet used it on my jasper stones.
Jasper often contains clear silica veins, or even inclusions of white quartz. Sometimes, being slammed against other stones by strong waves results in percussion surfaces running into the stone. Some of the close-ups of the red parts of the stone remind me of photos I have seen of Antelope Canyon in Arizona.
Jasper comes in many different colours, though in New Zealand we always think of it as a dark red stone. Patches of creamy brown and of different shades of green sometimes occur.
Jasper can be brittle and it is not unusual for small chunks to be missing. This means extra tumbling is required to remove them and the stone becomes much smaller as a result. This stone does not have this problem.
