metamorphic
Quartz Vein in Host Rock
Crystalline Silicon Dioxide (SiO2) in Pelitic or Shaly Matrix
Hardness: 7 (Quartz) vs 3-4 (Host rock), Color: White vein in dark gray/black matrix, Luster: Vitreous to dull, Structure: Crystalline vein within foliated or massive matrix, Cleavage: None (conchoidal fracture).
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Quartz) vs 3-4 (Host rock), Color: White vein in dark gray/black matrix, Luster: Vitreous to dull, Structure: Crystalline vein within foliated or massive matrix, Cleavage: None (conchoidal fracture).
Formation & geological history
Formed via hydrothermal activity where silica-rich fluids filled fractures in pre-existing rocks under high pressure and temperature during regional metamorphism or tectonic events.
Uses & applications
Primarily of interest to collectors or as a geological indicator for precious metals like gold. Industrially, quartz is used in glass and electronics; the host rock may be used in construction.
Geological facts
Quartz veins are the most common source of 'mother lode' gold. The sharp contrast between the white quartz and dark matrix is a classic example of hydrothermal deposition.
Field identification & locations
Identified by the distinct white band that can scratch glass (quartz) embedded in a softer, darker rock. Commonly found in mountainous regions with a history of tectonic activity.
More like this
