igneous and fossil
Obsidian and Fossilized Shark Tooth
Obsidian (Volcanic Glass) and Otodus sp. (Fossilized shark tooth)
Obsidian: Hardness 5-6, black, vitreous/glassy luster, amorphous structure, conchoidal fracture. Shark tooth: Hardness ~5, tan/brown, serrated edges, enameloid surface.
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Physical properties
Obsidian: Hardness 5-6, black, vitreous/glassy luster, amorphous structure, conchoidal fracture. Shark tooth: Hardness ~5, tan/brown, serrated edges, enameloid surface.
Formation & geological history
Obsidian forms from the rapid cooling of silica-rich lava. The fossilized tooth is a biological remain from the Cenozoic or Mesozoic era that underwent permineralization in a marine environment.
Uses & applications
Obsidian is used for surgical blades, jewelry, and decorative objects. Shark teeth are primary items for fossil collection and jewelry.
Geological facts
Obsidian fractures produce edges thinner and sharper than steel scalpels. Fossilized shark teeth are found because sharks lose thousands of teeth throughout their lives.
Field identification & locations
Identify obsidian by its glassy texture and sharp, curved edges. Identify fossil shark teeth by their triangular shape and presence of serrations or root structures. Commonly found in volcanic regions and coastal sediment deposits.
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