Colombianite, also known as Piedra Rayo, is an ancient form of obsidian (black) glass that closely resembles a tektite (hence its pseudotektie classification). Piedra Rayo translates to “Lightning Stone '' and is believed to have been the “Cintamani Stone” from sanskrit teachings and literature. It is estimated that these stones are around 30 million years old, which is extremely unique for any type of obsidian. It is a natural, highly energetic gem. Much rarer than Moldavite and Saffordite. Set in a 925 sterling silver.