Gemstones are mostly single mineral crystals, which are transparent and faceted. Translucent to opaque ones are often processed into plain ornaments, and the back part has starlight and cat's eye effects. Diamonds, rubies, sapphires, emeralds and golden-green cat's eyes are recognized as five precious gems, which have the value of preservation and collection, and the rest belong to middle and low grade gems.

1, diamond

Mineral diamond is the hardest substance in nature and is known as the "king of gems". It is best to be colorless and transparent. Colorless and bluish diamonds are called "fire and water diamonds" and have the highest value. Pink, blue, green and gold are rare and precious. Produced in South Africa, Australia, Russian and China, Liaoning, Shandong and other places. Cullinan is the largest gem diamond in the world, which is produced in South Africa and weighs 3 106 carats. China's national treasure "Chang Lin Diamond" is produced in Shandong and weighs 158.786 carats.

2. Ruby

The mineral name corundum is a precious gem second only to diamonds, with a hardness of 9, second only to diamonds. Produced in Myanmar, Thailand, Sri Lanka and other Southeast Asian countries. Myanmar is the main producing area of high-quality rubies in the world, among which "pigeon blood red" is the best, followed by pomegranate red and rose red. Ruby is the birthday stone in July, symbolizing enthusiasm and noble character, and has been loved by the world for thousands of years.

3.sapphire

The mineral composition is the same as ruby, so it is called "sister gem". Sapphire in a broad sense includes all kinds of gem-grade corundum except red, and Indian-occupied Kashmir cornflower sapphire has the best quality, but it has been mined. In the past, high-quality sapphires were mainly produced in Myanmar and Sri Lanka, and those with brighter sky blue tones were better, followed by indigo and light blue, and were also produced in Shandong, Jiangsu, Hainan and other provinces in China. For the birthday in September.

4. Emerald

As an beryl mineral, it is known as the "king of green gems" because of its special crystal green. It is said that its green beauty is beyond the reach of any green gem. Emeralds are the best, and high-quality emeralds are all produced in Colombia.

5, golden green cat's eye

The mineral name is chrysoberyl, and its hardness is 8.5, which is second only to diamonds and rubies. There are many colors such as cyan yellow, honey yellow, yellow brown, etc., with deep honey yellow as the top grade, produced in Sri Lanka. When it has a color-changing effect, it is called metamorphic rock (emerald), which is green in sunlight and red in incandescent lamp. It is also a precious gem.

6.opal

Mineral opals have gorgeous color changes. The five colors with rich colors, bright colors, more reds and even points are the best, with black opal being the best, followed by white opal and fire opal; Produced in Australia.

7.aquamarine

As a kind of beryl mineral, the seawater is blue, especially the color is strong and bright, and its value with cat's eye effect doubles. Produced in Xinjiang, Yunnan and other provinces (regions).

8. Spinel

Alias Dahongbaozi, there are often red, blue and other colors, and the red color close to ruby is more precious. Red hornblende is easily mixed with ruby. 1660 The crown of the king of England was inlaid with a red spinel named "black prince Ruby", which did not appear until the 20th century. High quality spinel is produced in Myanmar.

9. Olivine

Named for its olive green, the one that looks like grandma green is the best, followed by thick green and yellow-green. It is a birthstone in August, produced in Hebei and Jilin.

10, topaz color

Topaz is a mineral with hardness of 8 and many colors, among which wine yellow and red are the most precious and colorless is the worst. The common blue topaz in shops is artificially colored, but it is quite narrow. It is the November birthstone, which is produced in Xinjiang and Yunnan.

1 1, Ziya House

This is a garnet mineral. Because of the chemical composition of this group of minerals, there are many varieties and colors, among which emerald-like garnet and blood-red garnet are the best.

12, moonstone

It is a feldspar mineral. Its pale blue glow is quite like the moonlight on an autumn night, hence the name. High-quality moonstone is produced in Myanmar, and its halo is light blue, golden yellow and silvery white, with light blue and golden yellow halo being the best. If there is cat's eye effect and "pupil", the value will double, and it is a popular gem variety. Some scholars believe that the famous "Heshi wall" is the moonstone.

13, Pearl

Known as the "Queen of Gems". It is the secretion of pearl mussels, and the minerals have become aragonite. There are two kinds of pearls: natural pearls and cultured pearls, and the big and round ones are the top grade. The mariculture pearls in Hepu, Guangxi, China are world-famous.

Preliminary Identification of Ruby and Sapphire

Ruby is gorgeous in color, crystal clear, shining with precious light, dense and hard, without cleavage, and is deeply favored by people. In addition, there are few known ruby ore bodies, and the price has soared. Therefore, fake and shoddy products abound, and artificial corundum technology is becoming more and more mature, so it is particularly important to identify true and false gems. Commonly used identification methods include hardness test, morphological observation, luminescence observation and spectral observation.

Ruby and sapphire are the hardest substances except diamonds on the earth, reaching Mohs 9 and shining like mirrors forever. Other possible substitutes have lower hardness than it. The hardness can be confirmed by standard hardness such as topaz (Mohs 8) and crystal (Mohs 7). Of course, you still have to watch the score with a magnifying glass of 10 times.

Raw natural rubies and sapphires are usually hexagonal barrels or columns. Due to the slow growth rate of crystals, hexagonal growth lines parallel to hexagonal crystals are produced, also known as hexagonal growth zones. Any hexagonal growth line or band must be natural rubies and sapphires.

Corundum has strong luminescence and its own characteristics, so it has identification significance. Burmese ruby emits red fluorescence in both short-wave and long-wave ultraviolet and X-ray (but it can't be judged that it is a natural ruby just by emitting red fluorescence). Ruby in Thailand emits weak red fluorescence in long-wave ultraviolet, but does not emit or emits weak red fluorescence in short-wave ultraviolet.

Observing the spectrum is of decisive significance for the identification of rubies and sapphires. Spectral characteristics of ruby: it shows a strong red double line at 6942/6928, which can extinguish itself and become fluorescence; The broad absorption lines of yellow, green and purple are weak at 6680/6592, and there are secondary lines at 4765/4750/4685.

Self-extinguishing fluorescent double line is very effective for detecting whether corundum contains chromium (Cr), even though purplish red and purple sapphires contain trace chromium. Based on this, it can be concluded that it is a natural ruby.

How to choose jadeite

The quality standard of emeralds is similar to other precious stones.

First look at clarity. As mentioned above, inclusions (impurities) are a proof of natural gems. However, the amount of impurities in gems is an important criterion to distinguish between good and bad gems. Emerald is commonly known as the "garden" of inclusions, and the less impurities, the more precious the emerald is.

Second, look at the color. You can't simply think that the darker the color, the better. You should first say that the color is "positive". The so-called "positive color" means bright green and pleasing to the eye. Of course, the stronger the pure green, the higher the value.

Third, look at cutting. Emerald cutting is not as strict as diamond cutting, but it can't be cut at will. Most emeralds are cut into rectangular trapezoidal shapes, which are called emeralds in the gem world. A good cutting process can better show the brilliance of gems.

Fourth, look at the size. Generally speaking, the weight of an emerald can be divided into less than one carat, several carats, or more than ten carats. The larger (heavier) the emerald particles with the same quality, the higher the unit price.

To sum up, the price of an emerald is determined by its purity, color, cut and size. You can choose appropriately according to your own budget.

Crystal identification

A, true and false crystal identification method:

(1) At first glance, rock crystals are often influenced by the environment and always contain some impurities. When you look at the sun, you can see faint or even tiny stripes or catkins. Fake crystals are mostly made of inferior crystal slag and glass slag. After polishing, coloring and imitation, there are no uniform stripes and catkin-like substances.

(2) Lick your tongue: Even in the dog days of hot summer, licking the surface of the crystal stone with your tongue will feel cold and cool. Fake crystals are not cool.

(3) Illumination: When the crystal is placed vertically in the sun, it can emit beautiful light from any angle. Fake crystals can't.

(4) Hardness: The hardness of the crystal is very high, and it will leave no trace when lightly scratched with gravel on the jewelry; If there are streaks, it is a fake crystal.

(5) Inspection with a polarizer: the rock crystal rotates 360 degrees under the polarizer, with four bright and four dark changes, while the fake crystal does not change.

(6) Check with dichroism: natural amethyst has dichroism, while fake amethyst has no dichroism.

(7) Magnifier inspection: under the transmitted light, the bubbles that can be found can be basically classified as pseudocrystals.

(8) Check with hair: If the crystal is placed on a hair, the human eye can see the double shadow of the hair through the crystal, it is a rock crystal, mainly because the crystal has birefringence.

(9) Test with a thermal conductivity meter: set the thermal conductivity meter to 4 squares of green to test the gem, and the rock crystal can rise to 2 squares of yellow, while the false crystal does not rise, and when the area is large, it will rise to 1 square yellow.

Second, how to choose crystal products?

A look at the selection of materials: crystal products with excellent selection of materials should not see gas-liquid inclusions with star-shaped, cloud-like and flocculent distribution. The texture is pure, smooth and crystal clear. If cracks and spots of different shades are found, they are defective.

Second, look at the workmanship: there are two kinds of processing techniques for crystal products, namely grinding and carving. Such as crystal necklaces, bracelets, earrings, etc. Belonging to abrasive products; Guanyin statue, painted snuff bottle, etc. It belongs to sculpture. A well-made crystal product should be exquisite, which can fully show the external beauty (shape, style, symmetry, etc. ) crystal products, but also to maximize its inner beauty (crystal clear, smart color).

Third, look at polishing: the quality of polishing directly affects the value of crystal products. The crystal must be polished with emery during processing, and rough production will make the surface of the crystal have friction marks. Good crystal products have good natural transparency and luster, which is "burning with fire" in the local dialect.

Fourth, look at the eye hole: for crystal products (such as necklaces, bracelets, beads), it depends on whether the eye hole is straight, whether the thickness of the hole is symmetrical, and whether there are small cracks. The hole wall must be clear and transparent without "white spots".

Look at the color: even the same crystal, the texture and color of different parts are different. It belongs to monochrome, and the chromaticity should be uniform; If there are tones on the same crystal, it is required that the tone lines are beautiful and generous.

Sixth, look at coordination: when buying crystal ornaments, try them on, depending on size, tightness and length. If it is inlaid ornaments, see if it is firm, straight and harmonious. You should also pay attention to whether the style and color of crystal ornaments are in harmony with your figure, skin color, face shape and clothing.

The value and price of artificial gem

As we all know, a gem should have three elements: beauty, durability and rarity. Some people think that it should have eight elements, namely, beauty, hardness, rarity, transparency, stability, strangeness, harmlessness and weight. For thousands of years, gems have accompanied human beings, which not only beautified and enriched people's lives, but also found that gems have the value of decoration, preservation, currency, medicine, collection and appreciation. Compared with natural gems, synthetic gems pay more attention to the characteristics of "beauty" and the value of "decoration". In terms of beauty and decoration, synthetic gemstones can be comparable to natural gemstones, and sometimes even exceed natural gemstones. Because synthetic gemstones are substitutes for natural gemstones, when we synthesize gemstones, we always require synthetic gemstones to be as close as possible to natural gemstones, and the more realistic the better, the highest grade of natural gemstones. Therefore, synthetic gemstones not only have beautiful color, good transparency, high hardness and large crystals, but also have no cracks and rafters, good quality, bright color, purity and flawless texture, which is equivalent to or superior to the corresponding natural gemstones. It can be seen that the products made of synthetic gemstones as jewelry decoration materials must be as beautiful as those made of similar high-grade natural gemstones. And high-grade natural gemstones are not only rare and hard to find, but even if they are obtained, the price must be surprisingly high; Synthetic gemstones are manufactured and produced in factories or laboratories. Not only can the output be controlled artificially, but the price is also quite cheap. Because of this, it is very natural for people to use synthetic gems as the main material of highly decorative fashion jewelry or imitation jewelry. Besides, these jewelry are beautiful and the price is very low. Most people can afford it, which is well received by the masses and the sales volume is getting higher and higher. As can be seen from the above, the main value of synthetic gems is decoration, which is beyond reproach.

However, it should be noted that the concept of whether the number of synthetic gems is "rare" is relative. Compared with the high-grade products of similar natural gemstones, synthetic gemstones are not uncommon; However, compared with similar natural gems or materials that can be used for decoration, the number of synthetic gems is still "rare". In addition, many famous synthetic gems, because of their age, will continue to increase in value over time, and some can even reach the level of collection.

The price of synthetic gemstones is quite cheap compared with natural gemstones with the same color and homogeneity. Its cheap range is related to the difficulty of synthesis method and the size of output. On the whole, its cheap range is between one ten thousandth and one tenth. For example, the price of pigeon blood red ruby ring surface synthesized by hydrothermal method is around 250 yuan per carat. If the natural pigeon blood red ruby is a high-quality product without cotton, crack, inclusion and growth line, its price should be about 25,000 yuan/carat, that is, about one thousandth of the price of pigeon blood red ruby synthesized by hydrothermal method; The price of glass cat's eye imitation natural gold-green cat's eye gem is about one tenth of the price. This is because the hydrothermal synthesis of ruby is difficult, the equipment is expensive and the output is low, so it belongs to synthetic gem. The production process of glass cat's eye imitation natural gold-green cat's eye gem is relatively easy, the equipment is simple, the output is large, it belongs to imitation gem, so the price is cheap. Compared with similar synthetic gems, due to different synthetic methods, the prices are quite different. For example, the price of ruby synthesized by flame melting method is much lower than that of ruby synthesized by hydrothermal method, because the ruby synthesized by flame melting method is burned by hydrogen and oxygen, and it can grow about 10 gram of ruby per hour. At the same time, each workshop can put a lot of equipment for production, and the output is large. The sales volume of its products is not calculated in carats like rubies grown by hydrothermal method, but in terms of how much per kilogram. At present, the domestic production of flame-fused rubies is generally about 400-650 yuan per kilogram, 1 kg is 1 1,000g, and 1 g is 5 carats, that is, the price of 5000 carats of flame-fused rubies is 400-650 yuan, and the flame-fused rubies per carat is 0. 1 yuan, which is about 2500 times cheaper than the ruby grown by hydrothermal method. It can be seen that the prices of similar gems grown by different methods are different because of the difficulty of the method and the size of the output. However, it is an objective fact that the price of synthetic gemstones is much cheaper than that of natural gemstones of the same quality.

Nandan meteorite is a national treasure.

According to historical records, in 15 16 (the eleventh year of Zhengde in Ming Dynasty), a huge meteorite fell in Nandan County, Guangxi. Due to the social conditions at that time and the inconvenience of transportation and information, the falling meteorite could not be found in time. By 1958, during the "steelmaking", the geological prospecting team found a lot of reddish-brown iron ore with rust marks on it. At that time, people were surprised to see these "iron ore" which could not be melted in the crucible, and reported it step by step until the relevant departments of the central government and the Chinese Academy of Sciences handed the matter over to the Institute of Geology for handling. After investigation and testing by experts, it is confirmed to be the earliest known iron meteorite "Nandan meteorite" (called iron meteorite because it contains a lot of iron-nickel alloy).

According to historical data and field analysis, Nandan meteorite exploded when it fell, so the scattered points were distributed in Fiona Fang for dozens of miles. Nandan meteorite is an iron meteorite with many kinds of minerals and the most complete samples. More importantly, it can obtain the information of each component of the initial meteorite from the stone. Meteorites are colorful, most of them have no molten shells, and there are "gas marks" left by the interaction between meteorites and high-temperature airflow. The study of them is helpful to understand the pressure and humidity, heat dissipation and heat conduction, the impact energy of meteorites on the ground, the physical and chemical changes of meteorite structure, the formation process of asteroids in the solar system and their environmental evolution. And then it can be used to study the surface erosion and the influence of cosmic rays when spacecraft pass through the atmosphere. Since 1993, Nandan meteorite has become the target of people with ulterior motives at home and abroad, and it has been fired at a high price in society. The loss of meteorites has destroyed the original data and characteristics that can be used to study the landing state of iron meteorites, and the loss is irreversible. Due to the influence of traffic, management and many other factors, the country failed to completely recover the large Nandan meteorite.

At present, there are 680 kg, 1000 kg, 300 kg and more than 2000 kg Nandan meteorites in Beijing Planetarium, Nandan Park, Guiyang Institute of Geochemistry and Nandan Museum respectively. For meteorites, the laws of many countries have clear protection provisions. Russia, France, the United States, India, Germany, Egypt and most other countries stipulate that falling objects in outer space are owned by the state. All countries in the world regard meteorites falling in their own territory as "national treasures". Only by leaving enough specimens can we exchange and study with other countries selectively and cautiously. Nandan meteorite is of little use to individuals, but it has extremely precious scientific value. Nandan meteorite has been plundered in large quantities, which does not rule out overseas instigation and high-priced acquisition. In human history, only more than 2,000 meteorites have been collected, and the number is extremely limited.

Nandan stone is very rare because of its large quantity and wide area. It is a rare "visitor" from outer space, which can provide us with very intuitive and important cosmic information. Many people in Nandan County of Guangxi bought and sold "Nandan Meteorite" for personal gain. At present, Nandan Stone is seriously lost in Nandan County, and its stock is very small. Many meteorites were scattered in the hands of local villagers for sale, and some were taken away by unknown units. According to the National Cultural Relics Protection Law, Nantong meteorite is a national polar cultural relic.