igneous
Quartz vein rock
Milky quartz (SiO₂) in altered host rock, likely quartz-bearing hydrothermal breccia
AI-generated identification · may be incorrectWhite to translucent, vitreous-to-greasy luster; quartz hardness 7, no cleavage, conchoidal fracture, hexagonal crystal structure, specific gravity about 2.65. Brown, dark, and orange areas are likely iron-oxide-stained or altered host rock and accessory minerals.
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Physical properties
White to translucent, vitreous-to-greasy luster; quartz hardness 7, no cleavage, conchoidal fracture, hexagonal crystal structure, specific gravity about 2.65. Brown, dark, and orange areas are likely iron-oxide-stained or altered host rock and accessory minerals.
Formation & geological history
Formed when silica-rich hydrothermal fluids filled fractures and brecciated rock, later cementing fragments with quartz. The age cannot be determined from the image and depends on the host formation.
Uses & applications
Used as a silica source for glass, ceramics, and industrial materials; attractive pieces are collected as mineral specimens, though this example appears rough and mainly geological rather than gem quality.
Geological facts
Milky quartz contains microscopic fluid inclusions, fractures, and impurities that scatter light. Iron oxides commonly produce the rusty brown and orange staining visible here.
Field identification & locations
Identify by its glassy white appearance, hardness, lack of cleavage, and inability to scratch it with a steel knife. Common in hydrothermal veins worldwide, including mountain belts and old mining districts.
