Black is the most common color for obsidian but can also be found in light brown, brown mottled with black, and black with a golden or silvery sheen. Snowflake obsidian is dotted with white patches (ash) that have begun to crystallize. Gemologists consider the rainbow obsidian with purple, green and gold bands of sheen the most prized obsidian.
Obsidian helps to protect against depression. Obsidian helps block negativity of any kind. As a black gemstone, it symbolizes self control and resilience. Black stones have protective energies in the sense that black is the absence of light, and therefore, can be used to create invisibility.