Obsidianites

This variety of obsidian occurs as subrounded to subangular bodies up to about 2 inches in diameter, often bearing indented surfaces. 

Also known as marekanite and Apache Tears. 

The name "Apache tear" comes from a legend of the Apache tribe: about 75 Apaches and the US Cavalry fought on a mountain overlooking what is now Superior, Arizona, in the 1870s. Facing defeat, the outnumbered Apache warriors rode their horses off the mountain to their deaths rather than be killed. The wives and families of the warriors cried when they heard of the tragedy; their tears turned into stone upon hitting the ground