Mahogany aka Red Obsidian Volcanic Glass

Fully polished mahogany obsidian gem-grade stone.  Although it has a triangular shape the sides are not perfectly symmetrical.

The lower edge of one side has a small section that's not quite as well polished as the rest of the stone.  It can just about be seen in our second photo.  Look at the right side of the edge just above the shadow.

The colour of mahogany obsidian comes from the presence of iron oxides, usually hematite or limonite.  One of the most common iron oxides is rust.

Obsidian is molten magma that cooled too rapidly for crystals to grow.  Where crystals are present they're microscopic.  Being largely void of crystals means obsidian is not a mineral.  Minerals are made up of crystals.

Being a natural glass obsidian has an exceptionally smooth texture.  The edges of rough obsidian can be exceptionally sharp and in fact it's one of the sharpest natural materials.