mineral
Quartz-rich hydrothermal vein rock
Milky quartz with iron-oxide staining, possibly quartzite or silicified host rock (SiO₂)
AI-generated identification · may be incorrectPredominantly white to gray, massive quartz with dull-to-glassy luster and irregular fracture; hardness about 7 Mohs, no cleavage, and specific gravity near 2.65. Rust-orange areas likely limonite/goethite, with possible mica or altered host-rock fragments.
Identified More mineral →
Explore Quartz-rich hydrothermal vein rock in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Predominantly white to gray, massive quartz with dull-to-glassy luster and irregular fracture; hardness about 7 Mohs, no cleavage, and specific gravity near 2.65. Rust-orange areas likely limonite/goethite, with possible mica or altered host-rock fragments.
Formation & geological history
Likely formed when silica-rich hydrothermal fluids filled fractures and crystallized as a quartz vein, later weathered and iron-stained; exact age and host rock cannot be determined from the photograph. If heavily recrystallized, portions may represent quartzite rather than a vein.
Uses & applications
Commonly collected as a mineral specimen; attractive pieces may be used for lapidary work or decorative stone, but this rough, heavily fractured material has limited industrial or jewelry value.
Geological facts
Quartz is one of Earth’s most abundant minerals and is the principal component of many hydrothermal veins. Iron oxides commonly produce the yellow, orange, and brown surface colors seen here.
Field identification & locations
Test a fresh surface for glass-scratching hardness and inspect with a hand lens for quartz grains or crystal faces; fizzing with dilute acid would indicate carbonate rather than quartz. Common in mineralized mountain belts worldwide, including hydrothermal vein districts.
