Phenakite is a rare mineral, found as white or colourless 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 cheat). Transparent crystals are faceted for that collector, and are hard and bright.
Phenakite occurs in pegmatites, granites and mica schists. 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.