igneous and mineral
Obsidian and Phantom Quartz
Volcanic Glass (SiO2 + MgO + Fe3O4) and Crystalline Quartz (SiO2)
Obsidian: Hardness 5-5.5, jet black, vitreous luster, amorphous; Phantom Quartz: Hardness 7, clear with internal 'phantom' growth layers, vitreous, hexagonal system
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Physical properties
Obsidian: Hardness 5-5.5, jet black, vitreous luster, amorphous; Phantom Quartz: Hardness 7, clear with internal 'phantom' growth layers, vitreous, hexagonal system
Formation & geological history
Obsidian forms from rapid cooling of felsic lava; Phantom Quartz forms when mineral deposits (chlorite or hematite) coat a crystal surface during a pause in growth, followed by continued quartz formation
Uses & applications
Predominantly used for ornamental jewelry, spiritual healing practices, and gemstone collecting
Geological facts
Obsidian was used in the Stone Age for sharp tools and mirrors. Phantom Quartz is highly prized by collectors as 'ghost' crystals because they visually map the history of the crystal's growth.
Field identification & locations
Identify Obsidian by its conchoidal (shell-like) fracture and smooth glassy surface. Identify Phantom Quartz by looking for translucent 'v' shapes or internal ghost-like inclusions inside a clear bead.
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