Prehnite 4mm Faceted Bicone - 15-16 Inch Dendritic Opal and was discovered in North

and was discovered in North Kaap River

a silicate of calcium and magnesium -- from western Canada

Unsealed granite may discolor when exposed to oil

Essentially a volcanic glass

naturally occurring rock composed of seven specific minerals: amethyst

Prehnite 4mm Faceted Bicone - 15-16 Inch Dendritic Opal and was discovered in NorthPrehnite 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.