Prehnite 4mm Round AAA Grade - 15-16 Inch 16-inch Rounds Emerald and Heliodore -- and

Emerald and Heliodore -- and is often cut to highlight its chatoyant qualities

one of the most recognized turquoise-producing regions in the world

This semi to translucent stone occurs in an array of hues

Sardonyx is sometimes treated to bring out its reddish tones

Prehnite 4mm Round AAA Grade - 15-16 Inch 16-inch Rounds Emerald and Heliodore -- andPrehnite was the first mineral to be named after a person: its discoverer, Dutch Colonel Hendrik Von Prehn. Von Prehn discovered the stone in South Africa in 1774. Prehnite is translucent to transparent, in colors from light green to yellow green to olive, with occasional inclusions of Black Tourmaline that crisscross the stone in fibrous patterns. It is a phyllosilicate composed of silicon, calcium and aluminum with trace amounts of iron.