This is one of the rarest of gem-stones, and is highly prized by collectors. The crystals, which arc prismatic or with a thick, tabular habit, range from colorless to deep bluish green, but the best specimens are a very delicate bluish green. Nevertheless, phosphophyllite is rarely cut, as the material is brittle and fragile, and large crystals are too valuable to be broken tip.

The finest crystals, and the only ones to be faceted, are from Bolivia. Other localities include Germany and New Hampshire (USA).

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