Prehnite 8mm Round Faceted A Grade - 15-16 Inch 15x20-20x30 Black Eye Agate is a

Black Eye Agate is a variety of Sardonyx which has a Sard base

aluminum oxide and other metal oxides

Opalite is known by several other names

First discovered in 2006

Prehnite 8mm Round Faceted A Grade - 15-16 Inch 15x20-20x30 Black Eye Agate is aPrehnite 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.