Jadeite, found in Central America, which is more mottled and opaque than Oriental jade. It has been found in many shades of green, as well as ranging from grey to white. It was much used in pre-Columbian jewelry by the early Indians. In modern usage the term 'Mexican jade' is often a misnomer for a green-dyed variety of calcite or onyx.
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson