Phenakite is a rare mineral, found as white or colorless tabular crystals or stubby prisms. Twinning is common and distinguishes it from rock crystal with which it is often confused (hence its name, derived from the (Greek word for cheer). Transparent crystals arc faceted for the collector, and are hard and bright.

Phenakite occurs in pegmatites, granites, and mica schist's. The best crystals are found in the Urals (Russia), Brazil, and (Colorado (USA). Other localities include Italy, Sri Lanka, Zimbabwe, and Namibia.

A pebble weighing 1,470 carats was found in Sri Lanka, and faceted to a 569-carat oval and several smaller stones.