mineral
Gold-bearing quartz or iron-stained quartzite
Quartz (SiO₂), possibly with pyrite or native-gold flecks
AI-generated identification · may be incorrectRough, granular, pale gray to tan specimen with a sugary texture and scattered brassy sparkle; quartz hardness is 7, vitreous luster, no cleavage, and specific gravity about 2.65. The brassy grains may be pyrite (Mohs 6–6.5), but native gold cannot be confirmed visually.
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Physical properties
Rough, granular, pale gray to tan specimen with a sugary texture and scattered brassy sparkle; quartz hardness is 7, vitreous luster, no cleavage, and specific gravity about 2.65. The brassy grains may be pyrite (Mohs 6–6.5), but native gold cannot be confirmed visually.
Formation & geological history
Likely formed from hydrothermal quartz veins or metamorphosed quartz-rich rock, commonly associated with sulfide mineralization; its exact geological age cannot be determined from the image.
Uses & applications
Quartz-rich rock is used for aggregate, silica, and ornamental stone; pyrite is mainly a collector mineral. Gold-bearing material may have value only if assay confirms economically recoverable gold.
Geological facts
A brassy metallic appearance is commonly called “fool’s gold,” usually pyrite or chalcopyrite rather than gold. Gold is malleable and leaves a yellow streak, whereas pyrite is brittle and produces a dark greenish-black streak.
Field identification & locations
Test with a steel file, streak plate, and magnifier; gold is soft and malleable, while quartz scratches glass and pyrite crystals are brittle. Common settings include hydrothermal veins and gold districts worldwide.
