mineral

Milky Quartz / Chalcedony

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-white, milky, to translucent bluish-gray; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-white, milky, to translucent bluish-gray
Luster: Vitreous to waxy

Identified July 10, 2026More mineral →

Explore Milky Quartz / Chalcedony in the encyclopedia →

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Physical properties

Formation & geological history

Formed through hydrothermal processes or silica precipitation from cooling fluids in veins, geothermal environments, or sedimentary nodules. These specimens appear to be weathered nodules or vein fragments.

Uses & applications

Common quartz is used as an abrasive, in glass making, and as construction aggregate. While these specimens are low-grade, cleaner quartz is used in jewelry and electronics.

Geological facts

Quartz is one of the most abundant and stable minerals on Earth's crust. It can stay intact long after surrounding rocks have weathered away into sand.

Field identification & locations

Identify by its hardness (it will scratch glass) and lack of cleavage. Found globally in almost every geological environment; often found as pebbles in riverbeds or road gravel.