Mahogony Obsidian, from Glass Butte, Oregon, is a naturally occurring volcanic glass that's created when lava rich in feldspar and quartz is cooled too rapidly for crystals to form. It is a silica-rich semi-translucent black that has a large amount of reddish-brown color due to the magnetite or hematite that was present during formation. It exhibits conchoidal fracturing because it lacks crystal structure creating acute edges and is a hardness of 5 to 5.5 on the Mohs scale. In addition to its lapidary and decorative uses, obsidian has been used to make surgical blades and arrowheads. Stone Age people used obsidian for weapons and implements, Native Americans formed it into arrowheads and the Incans used it for weapons, mirrors and masks.  This material will take a great polish and is perfect for knapping.

Origin:  Oregon

Dimensions: 4" x 3.25" and approximately 5.8 mm thick.  Weight = 79 grams.

Shown wet.  Not polished. Known flaws are shown as white lines in the final picture frame.