igneous
Rough Quartz in Pegmatite Matrix
Quartz (Silicon Dioxide - SiO2) in Granitic Pegmatite
Hardness: 7 (Mohs scale), Color: Dirty white to light tan with reddish-brown iron staining, Luster: Vitreous to dull, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Identified More igneous →
Explore Rough Quartz in Pegmatite Matrix in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs scale), Color: Dirty white to light tan with reddish-brown iron staining, Luster: Vitreous to dull, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed from the slow cooling of magma deep underground, specifically in pegmatites where large crystals have room to grow. Geological age can range from hundreds of millions to billions of years depending on the host formation.
Uses & applications
Used primarily as aggregate in construction or as a source of silica for glassmaking and electronics (semiconductors). Low-grade rough specimens are often kept for amateur rock collections.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Specimens with reddish staining often get their color from secondary iron oxide infusions (limonite or hematite) that seep into microscopic fractures.
Field identification & locations
Identify in the field by its hardness (it can scratch glass), lack of cleavage, and translucent nature. It is extremely common in mountainous regions with granitic outcrops. Collectors should look for translucency on broken edges.
