Jade encompasses two minerals – jadeite and nephrite.  Jadeite is the more precious form and its emerald green almost transparent colour is highly prized in Asia and called “imperial jade”.   Nephrite is a stone of cultural importance in New Zealand (often referred to as “greenstone”) and was used for tools, weapons and for ornamentation.   A spinach-green variety is found in Russia.  Deposits are found in a number of countries.   Jade comes in green, white, orange, yellow, lavender, grey and black.  The white variety can be dyed.