Phosphophyllite is one of the rarest of gem-stones, and is highly prized by collectors. The crystals, which are prismatic or with a thick, tabular habit, range from colourless 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 up.
The finest crystals, and the only real ones to be faceted, are from Bolivia. Other localities include Germany and New Hampshire (USA).