Used by both Greeks and Romans as a decorative stone, chrysoprase, a translucent, apple-green stone, is the most valued variety of chalcedony. The color, derived from the presence of nickel, may fade in sunlight and stones may then be confused with fine jade.
Mines in Poland and Czechoslovakia once produced very fine chrysoprase. However, since 1965 the highest quality material originates from Queensland (Australia). Other localities are the Urals (Russia), California (USA), Brazil and Austria.
Another green chalcedony, prase, includes a more sombre hue and is very rare.