Pegmatite with quartz-albite-garnet-emerald

Description

Quartz-albite-garnet-beryl (emerald) pegmatite in the WVU Petrology collection. Sampling location unknown. The garnet and beryl are intergrown. The garnet is rimed with biotite where it is in contact with the albite feldspar. Pegmatites often include unusual minerals that contain volatile elements like Be (beryl), Li (spodumene, lepidolite), and F (topaz); this is the result of them crystallizing very late from a magma saturated in volatiles, and probably at low temperatures.