The Obsidian crystal stone meaning can be traced back to Paleolithic times where it was used to make arrowheads and other tools. Cherished for its deep, glossy sheen, Obsidian is often called volcanic glass because it is formed from molten lava that has cooled very quickly. During prehistoric times, the Obsidian crystal wasn't just a stylish way to accessorize a loincloth. This warrior stone also protected our Paleo-Indian ancestors from marauding invaders and the perils of hunting.