'This black glass named for its discoverer is formed by the high heat of a volcanic eruption'
Obsidian
GLASS: This black glass named for its discoverer is formed by the high heat of a volcanic eruption
This black glass named for its discoverer is formed by the high heat of a volcanic eruption
This black glass named for its discoverer is formed by the high heat of a volcanic eruption
GLASS
Obsidian
GLASS