Rare, beautiful Tinguait (a special type of Rhyolite) native to Russia. It has a very interesting pattern, half fingerprint and half picasso jasper. It has a slate gray-green color. Original hand sander. Grinded by us.
The stone is very hard, so it is suitable for practically any jewelry. But acid surprisingly bothers him (it loses its luster), so when tinning, use only acid-free soldering water, and it is better not to apply the patina to the stone either, only to the tin.