igneous
Pegmatitic Granite
Granite (composed of Quartz, Feldspar, and Mica)
Hardness: 6-7 (Quartz/Feldspar); Color: Pinkish-orange (orthoclase), translucent grey (quartz); Luster: Vitreous to pearly; Crystal structure: Phaneritic (large crystals); Cleavage: Perfect in feldspar, none in quartz.
- Hardness
- 6-7 (Quartz/Feldspar)
- Color
- Pinkish-orange (orthoclase), translucent grey (quartz)
- Luster
- Vitreous to pearly
Identified More igneous →
Explore Pegmatitic Granite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Quartz/Feldspar); Color: Pinkish-orange (orthoclase), translucent grey (quartz); Luster: Vitreous to pearly; Crystal structure: Phaneritic (large crystals); Cleavage: Perfect in feldspar, none in quartz.
Formation & geological history
Formed from the slow cooling of magma at great depths, specifically in the final stages of a magma body's crystallization where mineral-rich fluids create large crystals. Typically Precambrian to Paleozoic in age.
Uses & applications
Used in construction, as ornamental stone, crushed stone for road base, and a source for collecting quality mineral specimens like quartz and feldspar.
Geological facts
Granite pegmatites are the primary source of many gemstones and rare-earth minerals. This specimen shows particularly large interlocking grains of potassium feldspar and quartz.
Field identification & locations
Identified by large mineral grains (over 1cm) and salt-and-pepper or pinkish appearance. Commonly found in shield areas of continents or late-stage volcanic intrusions. Use a scratch test for quartz (7 Mohs).
