Lapis Lazuli (3) Raw Minerals Stones Rocks Collecting

Description

Origin : Chile

Lapis Lazuli 41-60 gr - cm 3.5-5 Raw Minerals Stones Rocks for Collection.

Lapis Lazuli is one of the gemstones known since the ancient age.
The etymology comes from the Latin lapis, "stone" and lazulum "blue".
The use of this gem dates back to the 5th millennium BC, at a time when it was widely used, for example, for the manufacture of jewels found in Pharaonic tombs in Egypt.
With lapis lazuli, through grinding and other processes, the most precious blue of medieval frescoes was created, with an intense and extremely resistant tone over time. The cost of this raw material was comparable to that of gold, as the only known mines were in Afghanistan.
Lapis lazuli consists of a high concentration of lazurite with associated other accessory minerals such as calcite and pyrite inclusions. The stone is predominantly of an intense blue color (but there are also samples of a color closer to light blue, depending on the amount of calcite).
Lapis lazuli is found in deposits especially in Afghanistan, China and Chile. It is also present in some effusions from volcanoes in Campania and Lazio.
Chemical-physical characteristics:
Hardness (according to the Mohs scale): 5.5
Density: 2.75 g/cm³
Cleavage: absent
Fracture: irregular
Color of the powder/smear: blue-grey
Luster: earthy
Fluorescence: mottled yellow-pink
Chemical formula: (Na,Ca)8[(SO4/S/Cl)2/(AlSiO4)6] + Fe2+