This is an Apache Tear – a piece of obsidian formed by volcanic activity millions of years ago.
These artifacts of molten glass were formed during one of the epochs that birthed the Superstition Mountains. Years ago, you could collect them by the dozens in the desert.
The legend surrounding these stones is a part of the sordid history of the United States. In the 1870’s, US Cavalry surrounded a group of about 75 Apache warriors, and as the story goes, rather than surrender or face defeat, the warriors rode their horses off a cliff near what is now Superior, AZ.
The wives and daughters of the warriors cried when they heard, and their tears turned into stone upon hitting the ground.