Green Chalcedony is a type of quartz that is usually found in shades of green. It is composed of two minerals, JASPER and prase, which are both silicates. JASPER is a form of chalcedony that is usually red or brown in color, while prase is a form of chalcedony that is usually green or yellow. PLASMA is a type of quartz that is usually found in shades of blue or purple. All three minerals are often found together in Green Chalcedony, giving it its unique coloration.