The finest lapis lazuli is mined in north-eastern Afghanistan and has been for over 6000 years making it one of the great gemstones of antiquity. Up until the middle ages, lapis was referred to in ancient texts as ‘sapphirus’ or sapphire by the Egyptians, Romans, Greeks and even the Bible. Unlike most gemstones that are minerals, lapis lazuli is actually a rock composed predominantly of lazurite, calcite, pyrite and other minerals.
The best quality lapis is said to resemble a clear starry night sky with an even deep violet-blue colour that is free of white calcite and has finely dispersed golden pyrite crystals throughout. Although Afghanistan has long been the world’s most important source of lapis in terms of both quality and quantity, Chile is the world’s second most important producer. Unfortunately Chile’s deposits are nowhere near that of Afghanistan’s as the Chilean material often contains too much calcite and or pyrite making it overly grey or pale.
Mohs’ Hardness: 5-6
Specific Gravity: 2.45-3.00
Refractive Index: 1.500
Optic Sign & Character: Aggregate
ICA Code: N or T
Purpose: To create a more even tone
Durability: Fair to good
Special Care: Avoid heating and chemicals
Synthetics: Reconstituted Lapis
Possible Imitations: Glass, plastic, dyed jasper