
mineral
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
AI-generated identification · may be incorrectHardness 7 Mohs; white to honey-yellow, translucent to opaque, with a vitreous-to-waxy luster and conchoidal fracture. It has a trigonal crystal structure and no cleavage; the rounded shape indicates tumbling or natural water wear.
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Physical properties
Hardness 7 Mohs; white to honey-yellow, translucent to opaque, with a vitreous-to-waxy luster and conchoidal fracture. It has a trigonal crystal structure and no cleavage; the rounded shape indicates tumbling or natural water wear.
Formation & geological history
Quartz crystallizes from silica-rich igneous, metamorphic, and hydrothermal fluids; milky appearance comes from microscopic fluid inclusions. The specimen’s exact geological age and source cannot be determined from the image.
Uses & applications
Used as a lapidary and decorative stone, in jewelry, countertops, glassmaking, abrasives, and electronics. This appears to be a common polished or naturally rounded specimen.
Geological facts
The yellow coloration may reflect iron staining or included iron minerals rather than true citrine. Quartz is one of Earth’s most abundant and chemically resistant minerals.
Field identification & locations
Identify by its glassy appearance, hardness, lack of cleavage, and inability to scratch it with a steel knife; it should scratch glass. Common sources include Brazil, Madagascar, the United States, and worldwide quartz-bearing rocks.