Chrome chalcedony (unlike chrysoprase) may also contain tiny black specks of chromite. Helaine controls a sapphire, onyx, agate, and chrysoprase. Gemstones such as sapphire, opal and chrysoprase are also mined in commercial quantities. The darker varieties of chrysoprase are also referred to as prase. It grows in rocky skeletal soils often among outcrops of chrysoprase. Chrysoprase, Greek "chrysoprasos", the tenth foundation stone of the celestial Jerusalem (Apoc., xxi, 20). Chrysoprase was mined at Pipalyatjara until recently.