What is a dyed gem?
Dyed gemstones are pigments, chemicals, animal blood, etc., which dye colorless or light-colored stones to bright colors to achieve good gem color effects. Among them, jade is more common, and almost all kinds of gemstones exist, but it is a common problem.
Dyed gemstones
Changing a colored gem means that it is artificially treated to add color or discolor. Such as gray, gray-blue agate, burned at high temperature, making it brownish red. The most common color-changing topaz (recognized in the market), the colorless and transparent topaz (relatively high yield), irradiated by rays (such as y-rays), turns into blue topaz (small amount) Can be yellow).
Common dyed gemstone varieties
First, jade
The value of jade is mainly determined by the color. The brighter the color, the higher the value. However, most of the jadeite materials are white or light-colored. By artificially dyeing the pigment into jade, a good color effect has been achieved to counterfeit jade. Dyed jade is also known as C goods.
Dyeing jade, no matter what color you dye, you can see the color precipitated in the crack by strong light.
Usually, the medium-thick structure is used, and the jadeite with a certain porosity is used as a raw material, and the color is deepened therein by heating and long-time immersion in the dye to improve the color. It is also that the dye penetrates into the structure of the jadeite, and the green color of the green jade is easily concentrated in the small crack, and is filled along the crack in the grain gap near the crack, and is distributed in a mesh shape. Before the soaking, the dilute acid is used to wash away the oil stains and surface impurities, and the jadeite is also left with pickling lines. These two are important features for distinguishing dyed jade.
Second, crystal
Crystals are usually colored in deep colors, and the price is also divided into shades. Therefore, crystal dyeing is also very common. It is bound to be a large wholesale market and there are many such goods, which are common in citrine and powder crystal. There is also a common variety "popcorn crystal".
Dyeing powder crystals, also see the staining marks to see the color in the gap
The dyed crystals have a large loss of crystals and a change in internal structure. Bad merchants will use this to pretend to be a watermelon tourmaline.
Crystals that pass through the heated crystals are quenched in the dye solution, resulting in dyed variants due to dye penetration. The color of the slightly dyed crystal is not deeply penetrated, and the color will fade after a long time. The interior of the heavily dyed crystal varies greatly.
Third, pearl
Dyed pearls are very common and are not easily identifiable and need to be enlarged to distinguish them. The dyeing of pearls is usually done by soaking dilute silver nitrate and aqueous ammonia solution, which makes the color of the pearls very similar to the natural pearls of the same color, and the treated color is stable to light and heat.
Dyed pearls, black concentrated in nacre
A string of good pearls, under magnified conditions, will see the dye concentrated in the vicinity of the bead hole or distributed in the veins throughout the bead.
Fourth, coral
Corals are better with red color, while most corals are white, and a lot of dyed corals appear to improve color!
Carbonate corals can be dyed. Magnification observation shows that between the calcite particles, the color in the crack is deep, and the dye can be wiped off with a cotton swab dipped in acetone. Natural black coral is shiny and dull after dyeing.
Five, turquoise
Use light green, moon white turquoise, and put it in blue aniline dye. It can be artificially dyed by means of a colored material such as blue wax or blue plastic, which is difficult to identify.
Dyed turquoise, uneven color distribution
A drop of ammonia on the dyed turquoise will fade the dyed blue. In addition to the conventional gemstone physical properties test, the dyed turquoise is also identified by a combination of infrared spectroscopy and X-ray diffraction.
Six, corundum
The gemstone is heated and quenched to form a microcrack and then immersed in the colorant, and the color of the precipitated pigment is a gemstone color. Sometimes dyes and oils are used together to improve the color of corundum.
Use a magnifying glass or microscope to observe the presence or absence of staining in the color. At the same time, you can use a cotton swab filled with acetone to wipe the gem to check.
Seven, Opal
There are many methods for opal dyeing, which is probably determined by the nature of the opal porous. Because the black opal is loved by people, the most common color is the black opal.
The color of the "black" opal treated by sugar acid is more rigid, relatively floating, and the graininess is obvious.
More sugar acid method is used. This method can blacken Australia's gangue opal. This opal contains many kaolinites. The white light scattered by kaolinite makes the opal's color dim and the color change is not obvious. After blackening, the excess white light is absorbed by the black charcoal deposited in the pores, thus enhancing the color of the opal, making it look like a high-grade opal.
Eight, lapis lazuli
Poor quality lapis lazuli is often dyed to enhance color effects.
Careful observation of the dyed material reveals that the color is enriched along the gap.
to sum up
The gemstone material that is usually treated contains a certain degree of porosity (porous loose or multi-cracks, cracks) so that the colorant can be immersed inside the gemstone. For gems that do not have pores, it is necessary to artificially create pores or cracks so that the colorant enters the crystal. Therefore, dyed gemstones usually have two major characteristics: crack cracking and loose porous structure.
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