igneous
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions
Hardness of 5 to 5.5 on the Mohs scale, black color with distinct white or grey snowflake-like patterns (cristobalite), vitreous to dull luster, amorphous crystal structure (volcanic glass), conchoidal fracture, specific gravity of approximately 2.35 to 2.40.
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Physical properties
Hardness of 5 to 5.5 on the Mohs scale, black color with distinct white or grey snowflake-like patterns (cristobalite), vitreous to dull luster, amorphous crystal structure (volcanic glass), conchoidal fracture, specific gravity of approximately 2.35 to 2.40.
Formation & geological history
Formed when felsic lava extruded from a volcano cools rapidly with minimal crystal growth, and over time, cristobalite minerals crystallize within the glass to form the characteristic snowflake patterns. Associated with volcanic activity and can be found globally.
Uses & applications
Widely used in jewelry making, ornamental objects, beads, and historically for sharp tools like arrowheads and blades.
Geological facts
Obsidian has been used by humans for thousands of years to create cutting tools because of its extremely sharp conchoidal fracture edges. The 'snowflakes' are actually clusters of tiny cristobalite crystals.
Field identification & locations
Easily identified by its deep black base color and contrasting white radial snowflake patterns. Found in areas with past volcanic activity such as the western United States, Mexico, and Iceland.
