Lapis Lazuli Pendant
weight 16.5g, size 60x34mm (with bail)
Lapis lazuli is a rock, not a mineral: whereas a mineral has only one constituent, lapis lazuli is formed from more than one mineral.
The main component of lapis lazuli is lazurite(25% to 40%), a fe with formula: (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2. Most lapis lazuli also contains calcite, feldldspathoid silikate mineral (white), sodalite (blue), and pyrite (metallic yellow).
The finest color is intense blue, lightly dusted with small flecks of golden pyrite. Stones with no white calcite veins and only small pyrite inclusions are more prized.
The best lapis lazuli is found in limestone in the Kokcha River valley of Badakhshan province in northeastern Afghanistan, and these deposits in the mines of Sar-e-Sang have been worked for more than 6,000 years