Intrusive Igneous Rock - Pegmatite

By Alec Augustine

Physical Characteristics

The rock should be composed almost entirely of crystals that are at least one centimeter in diameter.

Most pegmatites have a composition that is similar to granite with abundant quartz, feldspar, and mica.

Some of the world’s best tourmaline, aquamarine and topaz deposits have been found in pegmatites.

Uses and How & Where is is Formed

Pegmatite rock has limited use as an architectural stone. However, pegmatite deposits often contain gemstones, industrial minerals and rare minerals.

It forms near the margins of a magma chamber during the final phases of magma chamber crystallization.