2004- 12- 17 17: 13

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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.

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" to obtain 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 injected opal. Natural opal can't be pierced by hot needles, but injected opal can be pierced, and it will produce the smell of plastic melting.

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.

Identification of crystal

The temptation from the 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.

Identification of olivine

Olivine is a kind of low-grade gem, with yellow in green, similar to olive. 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).

Identification of pearls

Colorful seawater pearls came out.

Pearls are divided into natural pearls and cultured pearls, and cultured pearls are divided into seawater pearls and freshwater pearls. Natural pearls are low in output and expensive; Moreover, cultured pearls can be produced in large quantities, so the price is much lower. 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. However, the inner core of cultured pearls is artificially made large round beads, so the outer coating is 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.

At present, imitation pearls often appear in the market, which are generally made of glass beads coated with fish scale powder or silver powder. Their luster is obviously different from that of real pearls, and their weight is also different, so people with a little experience can identify them. If you scrape off a nail or a knife, the true face of Lushan Mountain will be revealed immediately.

The jewelry industry has some experiences in identifying pearls, which are introduced as follows:

(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, while the fake pearls have no growth texture, only the coating can be seen.