igneous
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
Hardness varies from 6 to 7.5 depending on mineral constituents (quartz is 7, tourmaline is 7 to 7.5); color ranges from dark black to white/translucent; vitreous to resinous luster; irregular or massive crystal structure with coarse grain size.
Identified More igneous →
Explore Pegmatite with Tourmaline and Quartz in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness varies from 6 to 7.5 depending on mineral constituents (quartz is 7, tourmaline is 7 to 7.5); color ranges from dark black to white/translucent; vitreous to resinous luster; irregular or massive crystal structure with coarse grain size.
Formation & geological history
Formed from the slow crystallization of magma deep within the Earth's crust, often late in the crystallization of a granite magma chamber, allowing very large crystals to grow.
Uses & applications
Used as a source of rare-element minerals, gemstones, and industrial mineral specimens; popular with mineral collectors.
Geological facts
Pegmatites are famous for containing some of the largest individual crystals found on Earth, sometimes measuring several meters in length.
Field identification & locations
Identified by its extremely coarse-grained texture (interlocking crystals much larger than surrounding rocks), commonly found in ancient shield areas and mountain-building belts.
