igneous/metamorphic
Milky Quartz with Mica (Gneiss/Schist influence)
Silicon Dioxide (SiO2) with Phyllosilicates
Hardness: 7 (Quartz) to 2.5 (Mica); Color: Milky white with silver/metallic flecks; Luster: Vitreous to pearly; Crystal structure: Trigonal/Monoclinic; Cleavage: None for quartz, basal for mica.
- Hardness
- 7 (Quartz) to 2
- Color
- Milky white with silver/metallic flecks
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 7 (Quartz) to 2.5 (Mica); Color: Milky white with silver/metallic flecks; Luster: Vitreous to pearly; Crystal structure: Trigonal/Monoclinic; Cleavage: None for quartz, basal for mica.
Formation & geological history
Formed through the cooling of silica-rich hydrothermal fluids or within metamorphic zones (gneiss/schist contact). The specimen appears to be a river-worn cobble, rounded by water erosion over hundreds to thousands of years.
Uses & applications
Quartz is used in glassmaking, electronics, and construction. This specific specimen is primarily a decorative garden stone or a hobbyist's collector item.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. The 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during the crystal's growth.
Field identification & locations
Identify in the field by its hardness (will scratch glass), white color, and the presence of shiny, flat flakes that reflect light. Commonly found in riverbeds, glacial tills, and mountainous regions.
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