igneous
Pyrite-bearing granite with a golden sulfide inclusion
Granite; likely pyrite (FeS₂), possibly chalcopyrite (CuFeS₂)
AI-generated identification · may be incorrectGranite is coarse-grained, black-and-white, with quartz, feldspar, and mica; hardness 6–7, nonmetallic to vitreous luster. The inclusion is brassy-gold and metallic, consistent with pyrite (Mohs 6–6.5) or chalcopyrite (Mohs 3.5–4).
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Physical properties
Granite is coarse-grained, black-and-white, with quartz, feldspar, and mica; hardness 6–7, nonmetallic to vitreous luster. The inclusion is brassy-gold and metallic, consistent with pyrite (Mohs 6–6.5) or chalcopyrite (Mohs 3.5–4).
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in the crust, generally during Precambrian to Phanerozoic plutonic events. Sulfide minerals formed in fractures or hydrothermal zones during or after emplacement.
Uses & applications
Granite is widely used as dimension stone, countertops, flooring, monuments, and aggregate; pyrite is mainly a collector mineral and former sulfur source. Chalcopyrite is the principal ore of copper.
Geological facts
Pyrite commonly forms cubic crystals and is called “fool’s gold”; chalcopyrite is softer and often tarnishes iridescently. The visible specimen appears to be a natural sulfide-bearing granite fragment.
Field identification & locations
Identify granite by visible interlocking quartz, feldspar, and dark mica; distinguish pyrite from chalcopyrite by hardness and crystal form. Common in continental batholiths and hydrothermal ore districts worldwide.
