igneous
Milky quartz vein rock
Quartz-rich hydrothermal vein; primarily quartz (SiO₂), with minor iron oxides and possibly feldspar or mica
AI-generated identification · may be incorrectWhite to gray, locally rusty brown; vitreous to dull luster, massive interlocking crystals, no obvious cleavage, and irregular fracture. Quartz hardness is Mohs 7 and specific gravity about 2.65.
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Physical properties
White to gray, locally rusty brown; vitreous to dull luster, massive interlocking crystals, no obvious cleavage, and irregular fracture. Quartz hardness is Mohs 7 and specific gravity about 2.65.
Formation & geological history
Formed when silica-rich hydrothermal fluids filled fractures and crystallized, likely during late-stage activity in an older host rock; its exact geological age cannot be determined from the image.
Uses & applications
Common material is used as aggregate, silica feedstock, and specimens for teaching or collecting; translucent, clean pieces may be cut or polished, though this specimen appears mainly ornamental.
Geological facts
The milky appearance results from microscopic fluid inclusions, fractures, and impurities within quartz. Brown zones commonly reflect iron-oxide staining.
Field identification & locations
Identify by its hardness, glassy fracture, lack of cleavage, and inability to scratch it with a steel knife; it should scratch ordinary glass. Quartz veins commonly occur in metamorphic and igneous terrains worldwide.
