igneous
Quartz-rich pegmatite specimen
Hydrothermal/pegmatitic quartz aggregate, chiefly SiO₂, with probable feldspar and mica/accessory sulfides
AI-generated identification · may be incorrectCoarse, interlocking translucent-to-white quartz crystals with vitreous luster; likely Mohs 7, poor cleavage, conchoidal fracture, and specific gravity about 2.65. Creamy granular areas may be feldspar, while purple flecks could indicate minor amethyst or fluorite.
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Physical properties
Coarse, interlocking translucent-to-white quartz crystals with vitreous luster; likely Mohs 7, poor cleavage, conchoidal fracture, and specific gravity about 2.65. Creamy granular areas may be feldspar, while purple flecks could indicate minor amethyst or fluorite.
Formation & geological history
Formed from late-stage silica-rich fluids in a granitic pegmatite or hydrothermal vein, likely during cooling of an intrusive igneous body; exact geological age and locality cannot be determined from the image.
Uses & applications
Primarily a mineral-collecting specimen; quartz is used in glass, ceramics, electronics, abrasives, and jewelry, while feldspar is important in ceramics and glass.
Geological facts
The specimen’s irregular druse-like texture and mixed crystal sizes suggest cavity or vein growth rather than a uniform massive rock.
Field identification & locations
Identify by its glassy luster, lack of cleavage, hardness, and inability to scratch quartz with a steel knife; acid testing is unnecessary. Common settings include granite pegmatites and quartz veins worldwide.
