obsidian

Obsidian by saad

Properties
obsidian is found black,gray,dark green,red,yellow and pink.

where Obsidian is Found
obsidian is found in mexico, iceland, japan, obsidian cliff, Yellow Stone National park and ethiopia.

how obsidian is formed
During rapid cooling of lava, that cools so quickly that it turns into volcanoic glass.

Interesting Facts
obsidian has the same chemicals as granite. indians used obsidian for arrowheads and knife.