Tri-Flow Obsidian comes from Glass Butte Oregon, and is a gorgeous form of mahogany obsidian that often has multiple grains and currents of flow! Tri-Flow can make some designer grade cabochons, as the obsidian between is often pure and almost completely see through when held to light or cut thin enough, and the waves of pattern are often in layers! The color generally comes from Magnetite that was present in the lava flow! Tri-Flow Obsidian is getting harder and harder to come by, with the majority of the slabs on the market being old stock! It takes an excellent shine!
Measurements (inches - longest - approx): 7.6 x 5.2 x .33
The last photo has been taken dry so that you may see any defects. The other photos have been taken wet to simulate a polish.