mineral
Quartz-rich rock, likely milky quartz or quartzite
Quartz (SiO₂), possibly quartzite (recrystallized quartz sandstone)
AI-generated identification · may be incorrectWhite to pale gray, massive and opaque-to-translucent with a vitreous-to-waxy luster and irregular fracture; visible grains are poorly resolved. Quartz hardness is Mohs 7, with no cleavage and specific gravity about 2.65.
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Physical properties
White to pale gray, massive and opaque-to-translucent with a vitreous-to-waxy luster and irregular fracture; visible grains are poorly resolved. Quartz hardness is Mohs 7, with no cleavage and specific gravity about 2.65.
Formation & geological history
Could be a quartz vein fragment or quartzite formed by metamorphism of sandstone. Such material is common in Precambrian terrains and sedimentary basins; the photograph cannot establish geological age.
Uses & applications
Common quartz is used for glass, ceramics, abrasives, engineered stone, and industrial silica. This small specimen has little commercial or jewelry value unless unusually clear or attractive.
Geological facts
The angular shape and pale color are consistent with weathered vein quartz, but surface coating or alteration may obscure the texture.
Field identification & locations
Near 17.9°S, 51.7°W in Goiás, Brazil, quartz veins and quartz-rich rocks are geologically plausible. Test for hardness by seeing whether it scratches glass; a steel knife should not scratch it. A vinegar test is irrelevant because quartz does not react.
