Lapiz Lazuli

From The Gemology Project
Revision as of 16:41, 20 August 2012 by Barbra (talk | contribs) (G&G Articles on Lapis Lazulu 1934-1980)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Lapis Lazuli
Chemical composition rock consisting of lazurite, hauyne, calcite and pyrite
Habit aggregate
Fracture uneven
Hardness 5.5
Refractive index 1.500 - 1.670
Specific gravity 2.50 - 3.00
Lustre resinous to vitreous
Lapis Lazuli, Afghanistan
Lazurite, Calcite, Pyrite

Lapis lazuli is not a mineral, but a rock consisting of as many as 15 different minerals. It is a contact metamorphic rock with variable composition and varying physical properties, usually forming as the result of contact metamorphism of limestones. The primary minerals present in lapis are lazurite, hauyine, diopside, calcite and pyrite. In Egypt, lapis beads, carvings, scarabs and jewelry date back over 5000 years!


Lapis lazuli was being mined in the Badakhshan province of Afghanistan as early as the 3rd millennium BC,[2] and there are sources that are found as far east as in the region around Lake Baikal in Siberia. Trade in the stone is ancient enough for lapis jewelry to have been found at Predynastic Egyptian and ancient Sumerian sites, and as lapis beads at neolithic burials in Mehrgarh, the Caucasus, and even as far from Afghanistan as Mauritania.
In addition to the Afghan deposits, lapis has been extracted for many years in the Andes (near Ovalle, Chile), the Lake Baikal region of Russia; Siberia; Angola; Argentina; Burma; Pakistan; Canada; India; and in the USA in California and Colorado.

G&G Articles on Lapis Lazulu 1934-1980

The GIA has published all the G&G's from 1934 until 1980 online. The organization of the list by subject was done by Joseph Gill.