mineral
Quartz crystal with dark inclusions
Quartz (SiO₂), likely tourmaline- or chlorite-included quartz
AI-generated identification · may be incorrectTransparent to translucent, colorless to milky quartz with vitreous luster and irregular/conchoidal fracture; Mohs hardness 7, no cleavage, trigonal crystal structure, specific gravity about 2.65. The black inclusions cannot be identified confidently from the photograph and may be tourmaline, chlorite, iron oxides, or…
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Physical properties
Transparent to translucent, colorless to milky quartz with vitreous luster and irregular/conchoidal fracture; Mohs hardness 7, no cleavage, trigonal crystal structure, specific gravity about 2.65. The black inclusions cannot be identified confidently from the photograph and may be tourmaline, chlorite, iron oxides, or host-rock material.
Formation & geological history
Quartz crystallizes from silica-rich hydrothermal fluids in fractures, cavities, and pegmatites; inclusions formed earlier or simultaneously during crystal growth. The specimen’s geological age and locality cannot be determined visually.
Uses & applications
Used mainly as a collector specimen or decorative stone; clear, inclusion-free quartz may be cut as a gemstone, while industrial quartz is used in glass, ceramics, electronics, and abrasives.
Geological facts
Quartz commonly preserves inclusions as growth records and can display attractive phantom or “included quartz” patterns. A glass or steel scratch test can help distinguish it from softer look-alikes, but avoid damaging collectible surfaces.
Field identification & locations
Likely quartz if it scratches ordinary glass and shows hard, sharp crystal faces; black needle-like inclusions would favor tourmaline, while flaky green-black inclusions suggest chlorite. Common worldwide in hydrothermal veins and pegmatites.
