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Such different opals
The modern opal market is filled with a variety of stones and products made from them, and prices for these stones can vary more than a thousand times. The most important difference is what is being sold for the opal. In addition to synthetic stones, composite stones are also common in jewelry, the so-called doublets and triplets, in which only the upper or middle part of the stone consists of opal. In the doublets, under the upper opal part, there is a lining made of non-jewelry material, which sets off the opal lining. In opal triplets, a thin plate is made, placed in the middle part of the stone, a transparent quartz or glass overlay is placed above it, and a lining, as a rule, is opaque in the lower part. Many items are made from "base" opals - opals devoid of color play (opalescence). Often low-grade “noble” opals, which have increased porosity and low opalescence intensity, undergo refinement - impregnation, which, by filling the pores in the stone, makes its play more distinct. Another type of refinement is opal carbonation. During this process, opals soaked in organic matter are heated until they become charred. As a result, the pores filled with organic matter become black, and the brightness of opalescence against a dark background increases. Often the carbonization and impregnation processes are combined. Another “product” used to make jewelry inserts is boulder opal. Boulder opal is an opal with a fragment of the host rock. The most valuable among such opals are specimens in which the rock is located on the back of the cabochon and does not impair the external perception. A type of boulder opal is matrix opal - a rock interspersed with small opal aggregates. Matrix opals with the maximum density of such concretions are in the greatest demand. But no matter how the boulder and matrix opals look, they are not in competition with real "noble" opals. Another type of noble opal is crystal opal. These opals are transparent and translucent to the observer, while real opals are opaque or only translucent. There is also a "fire" opal. This opal is yellow, yellow-orange or orange-red, with opalescence of complementary colors. If opal is devoid of play, then it is called jelly opal.
In practice, in the trade of marine cultured pearls produced by mollusks of the species Pinctada maxima and Pinctada margaritifera, as a rule, they adhere to a system of 4 gradations: "A" ("D"), "AA" ("C"), "AAA" ( "A / B"), "AAAA" ("A"). ...
The lack of deep green and clear emeralds is often compensated by refining stones in color and clarity, as well as synthetic stones. Simulations are also used to a lesser extent for this purpose. ...
The stone, later called "dianite", macroscopically is a dense rock of cryptocrystalline structure, characterized by bluish-gray and blue colors. ...
From an inexperienced point of view, it may seem that the central part of the East European platform, namely the region of the Moscow region, is deprived of gems. ...
We are starting a new cycle of publications about great researchers in the field of gemology and mineralogy. ...
We continue the cycle of significant days and people in gemology and mineralogy ...
The main indigenous industrial sources of diamonds are kimberlites and lamproites – alkaline-ultrabasic rocks of ancient platforms, forming mainly tube-shaped bodies, dikes and veins. ...
The world's largest platform for trade with diamonds is the "Rapaport", the price lists which guided the vast majority of diamond merchants in the world ...
When a Gemological study of stones and other jewelry gemologists use a wide range of equipment ...
Defects in jewelry significantly affect its consumer properties as a luxury, a decoration or status of the accessory, and, accordingly, limit its scope or make completely unusable ...
During one of the diagnostic examinations in our laboratory, the study of jewelry inserts in jewelry imitating black diamond, identified a variety of boron carbide a black color ...
The definition of authenticity, including tributaria, jewelry is a highly demanded field of expertise associated with expertise of the jewelry. Very relevant these types of activities when making secured transactions or sale-purchase jewelry in the ...
As is known, the motivation of consumers is an important aspect that is of particular importance for the prospects of market development, diamond products are most often purchased on the occasion of significant events and celebrations as gifts. One ...
As is known, the motivation of consumers is an important aspect that is of particular importance for the prospects of market development, diamond products are most often purchased on the occasion of significant events and celebrations as gifts. One ...
The definition of a gemstones, its origin and methods of refinement, if such has been applied, is one of the main objectives of Gemological expertise by expert Gemological laboratories ...
The lab was presented the crystal, in appearance resembling a natural diamond. The stone had a light-green color, the shape close to octahedral, and the weight of 9.71 ct. Its size was of 11.79 x 11.61 x 9,69 mm. ...
In determining the authenticity of a diamond, a gemologist should determine: Is this diamond made of diamond and is it natural; Has a diamond been trimmed to improve color and or clarity; The quality characteristics of the diamond " ...
This note will be useful to jewelry owners who wish to return, exchange jewelry that does not meet the requirements and expectations of the consumer. ...
The color of most natural topaz is associated with radiation defects in the structure of the crystal lattice of the stone. But, as a rule, natural stones do not possess residual radioactivity. Exceptions can be stones with internal inclusions of min ...
For the first time, the term “Pigeon’s Blood” (“Pigeon Blood”) was introduced by GRS (Gemresearch Swisslab) in 1996 for the qualitative characterization of ruby color in gemmological reports. In 1998, rubies with gemological reports describing color ...
When buying a diamond, it is important to understand which components form the price of a diamond. ...
Verification of the gemstone for authenticity, as a rule, consists in checking the gemstone (insert) for compliance with the information stated during the sale-purchase ...
Everyone who ever bought or wanted to buy expensive jewelry with precious stones in the secondary market, faced with the need to check the stones in the product for authenticity and for compliance with the data stated by the seller. ...
Inclusions in stones is one of the diagnostic signs, because a detailed study of them can often help establish the nature of origin, the presence of external influences (refinement), and sometimes even the deposit and conditions for stone formation. ...
In Russian, the term “amber” is borrowed from Lithuanian from “gintãras” - the name of lithified resin fossils from the coast of the Baltic Sea. ...
All deposits of fossilized fossilized resins are of exogenous origin, that is, are associated with factors of geological processes acting on the Earth's surface and in the upper layers of the lithosphere. ...
