Golden Obsidian

Obsidian is natural glass, formed when volcanic lava comes into contact with water, cooling the lava too quickly for crystallization to occur. It is therefore amorphous, with no cleavage and fracture is conchoidal. Usually black, this gemstone can be brown or grey, and more rarely red, blue or green; colour can be uniform, with bands or spotted. Some inclusions give a metallic sheen; internal bubbles or crystals produce a snowflake effect or a coloured iridescence.