Obsidian Skull | Mexico | SiO2 | Polished Obsidian

Formed 90,000 years ago from lava in the Colli area, the Primavera Forest in Jalisco is the third largest deposit of obsidian in the world.
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They appear glassy because of the high silica content which made them a great choice as the first manufactured mirrors. They would polish obsidian so that one could observe themselves in the volcanic glass.
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Metaphysically obsidian is a protective stone. It is used to shield against negativity, psychic attack, mental stress, and tension.