Lazurite's identification method

2021-08-13

Lapis lazuli was called Qianlin, Jinjing, Jinyu, Qingdai in ancient China. Buddhism is called Venuli or Bi Liuli, which is one of the testimonies of the cultural exchange between the East and the West in ancient times. According to data, lapis lazuli was introduced to China from Afghanistan through the "Silk Road". It is usually produced as an aggregate with a dense block and granular structure. The colors are dark blue, purple blue, sky blue, green blue, etc. Lapis lazuli is also the main raw material for natural blue pigments.
Lapis Lazuli is selected with uniform color and no cracks, fine texture and no gold stars, followed by no white gold, which means that gold stars are evenly distributed. If the pyrite content is low, no gold stars appear on the surface and will not affect the quality. However, if the color of Venus is black or dark, or if the calcite content is too much to form a large area of white spots on the surface, the value will be greatly reduced.
Lapis lazuli, turquoise and zircon are the same birthstones in December.

Lapis lazuli, its craft name is "green gold". The Persian word for lapis lazuli is called "Rashuwaer", the Arabic word for "Rashuwaer", and the Hindi word for "Leijiwaer", both refer to lapis lazuli.
Lapis lazuli was loved by the emperors of the past dynasties because of its hue like the sky. The emperor used lapis lazuli to decorate the Temple of Heaven, topaz for the altar of earth, coral for the altar of the day, and white jade for the altar of the moon." The court clothes of officials of the fourth rank of the Qing Dynasty were topped with lapis lazuli.
Lapis lazuli usually has two meanings.
First, it refers to alkaline aluminosilicate minerals. Chemical formula (Na,Ca)7~8(Al,Si)12(O,S)24[SO4,Cl2(OH)2]. The sodium is often partly replaced by potassium, and the sulfur part is replaced by sulfate, chlorine and selenium. Since the research on the mineral lapis lazuli has not yet been thoroughly studied, there are other different ways of writing its chemical formula, for example: (NaCa)8(AlSi04)6(SO4,cl,S)2, at this time the mineral is equiaxed crystal system, refraction Rate N=1.50, dark blue, blue-violet, sky blue, light blue or green-blue.
Second, it refers to a rock dominated by lapis lazuli minerals, a cryptocrystalline aggregate containing a small amount of impurities such as pyrite and calcite. The cleavage is not developed, the fracture is uneven, and the streaks are light blue. It emits orange spot light under long-wave ultraviolet light irradiation, and white fluorescence under short-wave ultraviolet light irradiation. Light red under the color filter. Glass luster to waxy luster, refractive index N=1.502~1.505, relative density 2.7~2.9. Lapis lazuli slowly releases hydrogen sulfide when it encounters hydrochloric acid.
Lapis lazuli is glass to grease luster, and its hardness is 5.5. Lapis lazuli has unique blue, dark blue, light blue and light cyan colors, etc., according to its different colors and can be divided into: cyan jujube dark blue and thick but not black; Jin Gelang jujube dark blue and pyrite content Those with more minerals than lapis lazuli; those with light blue color and white calcite are named after the ancients used this stone as a medicine for growth. In ancient my country, the burial lapis lazuli had the saying: "For its color green, this is used for the road to ascend to heaven", and it was mostly used to make the emperor's burial vessel.
A good lapis lazuli is dark blue and pure in color, with no cracks, fine texture, and no calcite impurities. It does not contain Venus (pyrite) or has very beautiful Venus are top grade.
The origins are the United States, Afghanistan, Mongolia, Myanmar, Chile, Canada, Pakistan, India and Angola. The lapis lazuli of Afghanistan is produced in the lapis lazuli-bearing area of Badakhshan Province of the country, among which the Saresange deposit is the most famous. The genetic type of lapis lazuli jade deposit is contact metasomatic skarn type. The lapis lazuli produced in A country has a uniform dark blue to sky blue, and the extremely fine-grained cryptocrystalline structure is mixed with a small amount of pyrite, which makes it shine under the sun. Lapis Lazuli is called "treasure" by Arab Muslim countries.
Lapis lazuli can be used for both jade carving and jewelry. The lapis lazuli carving craftsmanship of our country is first-rate, especially after the founding of the People’s Republic of China, the lapis lazuli ornaments, mountains, pendants, and jewelry made by Beijing Jade Factory were exported overseas. The continuous fighting in Afghanistan has made it very difficult to import raw materials.
Lapis lazuli is a traditional jade imported from my country since ancient times, most of which originated from Afghanistan. So far, no production of lapis lazuli has been found in our country.

The granular structure of natural lapis lazuli can be seen under a magnifying glass, and often contains pyrite spots and white calcite clumps.
Lapis lazuli is generally blue, and its color is determined by the content of lapis lazuli minerals. Good lapis lazuli is dark blue and pure, with no cracks, fine texture, and no calcite impurities. It can be made into jewelry and so on. If there are white stone threads or white spots, the density, purity and uniformity of the color will be reduced, and the quality of the jewelry will be reduced.

The texture of lapis lazuli should be dense, delicate, without cracks, and the pyrite should be evenly distributed like sparkling stars. The local distribution of pyrite in flakes will affect the texture of the lapis lazuli jade, and the more obvious the cracks, the lower the quality level.