Obsidian is one of the sharpest naturally occurring materials. It breaks with a conchoidal fracture which is characteristic of most types of glass.
A round black obsidian mirror was used by an advisor to Queen Elizabeth I. He believed it enabled him to communicate with the spirit world.
The mirror which is housed in the British Museum was designed by the Aztecs in Mexico.
Obsidian is best known for being black but occurs in different colours and with various inclusions and sheens.
It's a non crystalline solid that forms when lava cools and solidifies.
This glassy rock is rarely older than a few million years because its resistance to weathering and erosion gradually breaks down.
MOTHER OF PEARL
