For collectors, it is necessary to have a sense of smell like a hound. When buying jewelry, pay attention to buying rare jewelry with good gem properties. These hard-to-find goods have a common feature, that is, they have the "rare" factor in the gem attribute, which may be divided into the following categories.

1. New variety

For example, zoisite Tanzanite, which is produced in Melella, Tanzania, will be described by Okamoto kenyon as the night sky of Kilimanjaro, which produces precious stones, changing from light blue to magnificent purple-blue, which is fascinating. The most striking feature of this zoisite gem is its strong polychromatic color, ranging from light blue to blue-purple. Such a unique and varied multicolor gives people a feeling of being as unreal as reality and as drunk as a dream. Multicolor phenomenon in the processing of general gemstones, try to make its appearance inconspicuous. For example, in sapphire, the table is usually perpendicular to the C axis when processing, which can avoid multicolor and keep pure blue. For tanzanite, people are obsessed with this ever-changing multicolor, which is also the attraction of this gem. Tiffany Company has a unique eye, and acquired and collected this gem, designed it as jewelry and named it "Tanzanite". Since then, tanzanite has swept the world jewelry market.

2. Characteristic varieties

3. Special specifications of gemstones (or large particles)

Some precious stones are rare because of the development of impurity cracks in inclusions, so large-grained precious stones have the potential to appreciate because of their rarity. For example, garnets larger than 3 carats and saffron larger than 5 carats mentioned above are scarce in the market, so the price is naturally high. Generally speaking, the bigger the gem particles, the rarer and more precious it is, and the higher the price. However, the rarity of different gems is different. For ordinary tourmaline stones, such as red tourmaline and green tourmaline, goods with a size of tens of carats are very common, while rubies with a size of more than 5 carats are rare, and sapphires with a size of more than tens of carats are even rarer. 5 carats of clean emeralds are very rare in the market, while aquamarine, which is also beryl, is common in dozens or hundreds of carats. Olivine is a common common gem, and its wholesale price is generally tens to hundreds of yuan per carat, but goods larger than 10 carat are rare, and its wholesale price is several hundred to thousands of yuan per carat. It can be seen that the size, specification and weight have a great influence on the price.

Some kinds of precious stones are the opposite. After the particles reach a certain level, the unit price decreases with the increase of weight. For example, the size, specifications and weight of aquamarine and opal are not sensitive to the price, and the unit price per carat of this gem does not change much when the weight becomes larger. Aquamarine and opal are more than 30 carats, and the unit price of weight will fall instead of rising! Because aquamarine is light in color, it is easy to gather color when it is big. When people feel the same hue, it means that the true color of large particles is lighter than that of small particles. The increase of aquamarine particles can deepen its color, but the color will appear gray-blue tone, which is not smart and bright enough. Too large particles are not suitable for jewelry, so the unit price of aquamarine exceeding 30 carats does not rise but falls. Opal is a kind of massive aggregate, and it is common to have large raw materials. When it is more than 30 carats, it needs to be cut to be suitable for processing into jewelry. Therefore, if the opal exceeds 30 carats, the unit price will fall instead of rising. Hetian jade seed material is an obvious example. The unit price of small seed material is higher than that of large seed material (see Appreciation and Valuation of Yu Shuo-Hetian Jade in Laohou).

Understand the characteristics of each gem. When you encounter a certain specification of gem or some special varieties of gem, you can judge the collection value of gem according to the rarity of the variety and gemmological characteristics. Even common gemstones such as olivine, tourmaline, topaz, crystal, jadeite and hetian jade have very rare and precious varieties.

4. Rare gemstone varieties

Some precious stones are very rare and are the curious objects of collectors and gem mineral lovers. As gem mineral specimens, they have research value. For example, the color of sphene is yellow-green, green, brown-green, and brown, which has strong polychromatic properties. One direction is green, and the other direction is yellow-green, brown. Mohs hardness is 5 5.5, refractive index 1.90 2.034, birefringence is 0. 130, and dispersion value is about 0.05 1. The high refractive index makes the gemstones on the carved stone surface have strong colors. Because the dispersion value of sphene is higher than that of diamond, it emits colorful light. The stronger the fire color, the richer the color and the higher the price. This kind of gem with higher fire color than diamond is her pride, and with this feature, many gem lovers are obsessed with it.

Sphalerite is a common mineral, but it is rare as a gem. It is another kind of gem with high refractive index and high dispersion value. The refractive index is 2.4, which is close to that of diamond, and the dispersion value is 0. 156, which is four times that of diamond. This kind of gem is not only radiant, but also colorful, giving people a rainbow-like impression, which is a feature that other colored gems does not have. When you meet this kind of gem, you should collect it.

5. New gem types

With the deepening of gem research, new gem varieties appear from time to time. According to Antoinette Marint, an exciting color-changing gem-diaspore was discovered in Turkey, which is a color-changing variety of diaspore and a little-known ore. Bauxite is beautiful and soft in color, which can change from light green to brown pink in sunlight or powder beige in indoor warm light. Diaspore is a newly discovered color-changing gem with hard texture and bright color, which is pleasing to the eye. Its size is over 65,438+00 carats, which is the advantage of diaspore over gold emeralds below 2 3 carats. This unique and unusual gem fascinates collectors and connoisseurs. If you have a chance to meet this new gem, curious hunters will not let it go easily.

This article is excerpted from "Practical Experience of Treasure Hunting Jewelry Selection of Lao Hou", titled P 144- 147. Author: Hou, please indicate the source. If you have any questions, please contact us and we will delete them immediately and apologize. Thank you!