1。 Identification of diamonds
Diamonds are the hardest natural substances. A diamond can carve any other gem, but no other gem can carve a diamond. Diamonds are also lipophilic. If you draw a line on the surface of a diamond with a pen, it will become a continuous straight line, while other gems will break intermittently. Under the magnifying glass of 10 times, we can see that most diamonds are hazy with triangular growth lines, and the surface of diamonds has "fire" light of "red, orange, blue" and other colors.
Similar or fake diamonds are as follows:
① Zircon: Very similar to diamond, it is the best substitute for diamond. The identification method is: when observing the processed zircon prism surface with a magnifying glass of 10 times, from top to bottom, you can see that there is obvious ghost on the bottom line, but there is no shadow on the diamond.
(2) Glass: The refractive index of glass is very low, and there is no flickering color light like diamonds; Especially when submerged in water, glass products are dull and exposed.
(3) Soviet diamonds: synthetic cubic zirconia, a synthetic compound, is very close to natural diamonds in dispersion and refractive index, and also has an attractive "fire" light appearance. But its hardness is low (8.5), so it can be distinguished from diamonds.
④ Crystal: Although crystal is a transparent crystal of natural minerals, it looks like a diamond after processing, but it lacks the colorful light of diamond.
2。 Identification of ruby
Natural gemstones have "ten Hong Jiu cracks", and natural rubies without any flaws and cracks are extremely rare. Artificial rubies have the same color, few internal defects or crystal inclusions, and are clean and large. As a precious gem, natural rubies over 3 carats are very rare in the market. If you encounter a big ruby, you should pay attention.
Natural ruby has a strong "dichroism". The so-called dichroism means that there are two colors of red and orange red from different directions. If there is only one color, it may be red spinel, garnet or red glass.
Red spinel and natural ruby are very similar, and they are most easily confused, so be very careful.
3。 Identification of sapphire
Natural sapphires are often uneven in color, and most of them have a flat growth line.
Natural sapphire also has obvious dichroism, one direction is blue, and the other direction is blue-green. Other gemstones are different in color from natural sapphires and can be distinguished.
4。 Identification of jadeite jade
In nature, there are many kinds of green transparent gemstones similar to emeralds, such as jadeite, tourmaline, fluorite, olivine, garnet, zircon, etc. Among them, tourmaline, fluorite and jadeite are easily confused because of their similar appearance to emeralds.
Visually, green jadeite is generally translucent, often in a patchy structure with interwoven fibers, while high-quality emeralds are transparent and crystal clear. Emerald hardness is 7.5-8, while fluorite hardness is very low, only 4. Emerald accounts for a small proportion, while fluorite, tourmaline and jadeite account for a large proportion. Zircon has strong dispersion and obvious ghost.
Artificial emeralds and green glass are similar to natural emeralds, and the biggest difference between them is that most natural emeralds have defects or inclusions, which shows dichroism.
5。 Identification of cat's eye
In recent years, there is a kind of glass fiber cat's eye ring on the market, which is embedded in gold or silver rings, making people unable to tell the true from the false.
The identification method is that when the torus is rotated, several light bands can appear at the arc top of the fake cat's eye at the same time, while there is only one real cat's eye.
The fake cat's eye line is rigid, while the real cat's eye line is flexible. True cat's eyes are mostly brownish yellow or light green, while fake cat's eyes are varied in color, including red, blue and green.
6。 Identification of opal
Opal can be divided into black opal, white opal and yellow opal by color, of which black opal has the highest price.
In order to improve the low-priced white or yellow opal, some people change its color artificially and become "black opal" in order to make high profits.
The main method is to boil with sugar or inject plastic to make the white opal black. The identification method is that the specific gravity of opal is obviously different after boiling sugar or injection molding, and the specific gravity value becomes lighter when tested in water. The heating needle can also be used to test the opal of injection. Natural opal can't be pierced by hot needles, but injected opal can be pierced, and it will produce the smell of plastic melting.
7。 Identification of tourmaline
Tourmaline is a kind of mid-range gem, but because pink and bright blue tourmalines are more expensive, there are also imitations.
There are two common imitations, one is artificial coloring with colorless tourmaline; One is made of red glass.
The identification method is that the real tourmaline often has obvious dichroism and can be seen as a ghost; Tubular inclusions or cotton wool can be seen in the body, and the crystal cross section is curved triangle. These characteristics are not possessed by imitations. The tourmaline dyed by workers is not difficult to identify because its color is dull and there is no "treasure light" of natural tourmaline.
8。 Identification of tanzanite
Tanzanite has a typical glass luster. Tanzanite is generally transparent or translucent.
Tanzanite is rich in color, including green, blue, gray, brown, yellow, yellow-green, green, blue and blue-purple with earthy tones, but blue and blue-purple are the main colors.
Tanzanite is very colorful, mainly three colors, that is, blue, purple, green and yellow. The multicolor color of brown tanzanite is green-purple-light blue yellow-green tanzanite is dark blue-yellow-purple.
The naked eye identification characteristics of tanzanite: high density, strong trichromaticity and unique blue-purple color.
9。 Identification of crystal
Rock crystals are clear and transparent, often containing cloud, star or flocculent gas-liquid inclusions, and often with microcracks. In addition, the rock crystal is polarized, and you can see the phenomenon of twin crystals, such as a crystal ball. Looking down from the top, there will be a double image.
Synthetic crystal or glass products are uniform and pure in the body, without cracks, and often have small bubbles inside. Looking down at the sphere, you can't see the ghost of the line below.
Through touch recognition, we can feel that the proportion of synthetic crystals is greater than that of rock crystals; Crystal stone feels cold and glass feels warm.
10。 Identification of olivine
Olivine is a kind of low-grade gem with yellow green and olive color. The most common counterfeit olivine on the market is made of stained glass.
The main difference between the two is that olivine has obvious "double shadow", while glass does not;
Crystal inclusions are often seen in olivine, and only bubbles are contained in glass. Olivine has a specific gravity of 3.5 and a hardness of 7, which is greater than that of glass (2.6) and hardness (6).
The main difference between them is that natural pearls and cultured pearls have no nuclei. The inner core of natural pearls is often just some sand or parasites, or even no inner core.
The inner core of cultured pearls is artificially made large round beads, so the outer coating is very thin. On the body surface, natural pearls rarely roll because of their random growth environment and poor roundness. The inner core of cultured pearls is round, so the roundness of pearls is better.
Natural pearls are transparent because of their long growth time, delicate texture, thick nacre, smooth skin and few "convex bubbles". The cultured pearls are thin in layer, rough in texture, "waxy" in luster, and have some uneven "bubbles" on the surface, so the transparency is poor.
If it is a perforated pearl, observe the hole carefully with a magnifying glass. If it is a cultured pearl, you can generally see a brown boundary inside the pearl, which is the boundary between the inner core and the pearl layer that grows later.
The jewelry industry has some experience in identifying pearls:
(a) the color, size, shape and luster of the beads. They are all identical, that is, artificial pearls. Because real pearls can't be consistent anyway.
The luster of real pearls is like a rainbow, colorful and very beautiful. Fake pearls are dull and have no colorful rainbow tones because of the coating on their surfaces.
③ Real pearls have good transparency, while fake pearls have poor transparency.
④ Real pearls have a smooth and cool feeling through hand feel, while fake pearls are often warm and greasy.
⑤ With a magnifying glass of 10 times, the growth texture can be seen on the surface of real pearls, but there is no growth texture on fake pearls, only the coating can be seen.