mineral
Iron-rich sulfide-bearing rock, likely pyrite-rich shale or limonite-goethite specimen
Likely pyrite (FeS₂) with oxidation products goethite/limonite (FeO(OH)·nH₂O), possibly in shale or quartz matrix
AI-generated identification · may be incorrectMetallic brassy-gold and silver-gray surfaces with earthy yellow-brown weathering; pyrite is Mohs 6–6.5, cubic crystal system, metallic luster, and no true cleavage, while goethite/limonite are softer (about 4–5.5) and dull to earthy.
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Physical properties
Metallic brassy-gold and silver-gray surfaces with earthy yellow-brown weathering; pyrite is Mohs 6–6.5, cubic crystal system, metallic luster, and no true cleavage, while goethite/limonite are softer (about 4–5.5) and dull to earthy.
Formation & geological history
Pyrite commonly forms in hydrothermal veins and sedimentary environments; exposed sulfides oxidize into goethite and limonite. The specimen’s exact age and locality cannot be determined from the photograph.
Uses & applications
Pyrite is collected and used historically for sulfur and sulfuric-acid production; iron oxides are pigments and iron ores. This rough piece has modest specimen value unless locality or crystal form is exceptional.
Geological facts
The bright gold color can resemble native gold, but pyrite is harder and commonly has angular or cubic forms; oxidation produces its brown-yellow coating.
Field identification & locations
Look for a heavy specimen, metallic luster, dark streak, and possible cubic faces; a streak test, hardness test, and specific-gravity or chemical test would confirm identification. Common worldwide in sedimentary basins and hydrothermal mineral districts.
