Milky Quartz

Hardness: 7 on Mohs scale; Color: Opaque white to translucent; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formed through the cooling of magma or by precipitation from hydrothermal veins. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. Can be found in geological formations of any age, from Precambrian to recent.

Used in the manufacturing of glass and ceramics, as an abrasive, and in electronics for its piezoelectric properties. In construction, it is used as an aggregate. Popular in landscaping and as a common specimen for gemstone collectors.

Milky quartz is the most common variety of crystalline quartz. Historically, it was used by many cultures to create tools and arrowheads because of its hardness and the way it fractures into sharp edges.

Identify in the field by its white color, inability to be scratched by a steel knife, and lack of cleavage (it breaks in irregular, curved surfaces). It is ubiquitous globally, often found as cobbles in riverbeds or as veins in mountain outcrops. For collectors, look for pieces with interesting surface textures or associations with other minerals.