Agni Manitite, tumbled

Medium tumbles, size and shape will vary. Also known as Pearl of Fire or Cintamani or Chintamani, these Indonesian stones look like obsidian at first, but they become translucent when placed in front of a bright light source. Often incorrectly referred to as a tektite, this stone is a type of obsidian, volcanic in origin, and has properties similar to those of apache tears.