igneous
Polished black granite with golden sulfide veining
Likely gabbro or black granite containing pyrite/chalcopyrite; exact identification requires testing
AI-generated identification · may be incorrectDark, coarse-grained crystalline rock with polished vitreous-to-waxy luster and irregular metallic-brassy gold veins. Likely Mohs 6–7, with abundant feldspar/pyroxene and sulfide minerals; no obvious cleavage at the specimen surface.
Identified More igneous →
Explore Polished black granite with golden sulfide veining in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark, coarse-grained crystalline rock with polished vitreous-to-waxy luster and irregular metallic-brassy gold veins. Likely Mohs 6–7, with abundant feldspar/pyroxene and sulfide minerals; no obvious cleavage at the specimen surface.
Formation & geological history
An intrusive igneous rock that crystallized slowly from magma, probably during Precambrian to Phanerozoic continental crust formation; the gold-colored material likely formed later in fractures through hydrothermal mineralization.
Uses & applications
Commonly used as decorative dimension stone, countertops, tiles, monuments, and polished slabs; the sulfides add visual appeal but usually do not indicate economic gold.
Geological facts
The golden areas may be pyrite (“fool’s gold”), chalcopyrite, or iron-stained quartz rather than native gold. A streak, hardness, magnetism, and acid test would help distinguish the minerals.
Field identification & locations
Look for interlocking black crystals and reflective brassy grains; pyrite is harder and more brittle, while chalcopyrite is softer and may tarnish iridescently. Similar black-gold stones occur in India, Brazil, China, Finland, and North America.
