Origin: Glass Buttes, Oregon, U.S.A.

Description: Black butter obsidian is a favorite among flintknappers because it isn't as brittle as some of the glassier ones. It is unique because it is opaque, rather than translucent. The surface has a satin finish when spalled.

Chemical Composition: Primarily silica (SiO2), with aluminum, iron, magnesium, calcium, sodium, and potassium in smaller amounts depending on the lava source.

Grade: Lapidary Grade
Appearance: Opaque
Cracks: None
Inclusions: None

Approximate Size of 1 pc: 14cm x 7cm x 2cm
Approximate Weight of 1 pc: 280g

Rough is rough. We do our best to grade and describe pieces in the lot, but ultimately, they all differ.