What do gems mainly include? Which is the best? Do you have any store recommendations?

Gemmology divides gems into three categories according to their uses: colored gems [7], diamonds and jadeite.

Diamond:

Diamonds with transparent colors are precious gems. Because of its high hardness, high brightness and fire color (strong dispersibility), it has become the most popular gem, among which transparent or blue has the highest value. The main criteria for evaluating diamonds are weight, color, cleanliness and cutting.

Colored gems:

Refers to those colored gems, such as rubies, sapphires, emeralds, aquamarine, cat's eye gems, color-changing gems, topaz gems, opals, tourmalines, spinels, garnet gems, danquan stones, topaz, zircon gems, olivine, emeralds, quartz cat's eyes (cat's eyes), turquoise, lapis lazuli, pearls, etc.

Emerald:

This category is specially divided for China people, and refers to polycrystalline aggregate minerals such as jadeite and white jade. Whereas diamond and colored gems are single crystals.

Jade is divided into white jade, jasper, sapphire, jet, topaz, topaz, green jade, Beijing white jade and so on. Geographically, there are Xinjiang jade, Henan jade, xiuyan jade jade (also known as Xinshan jade), Australian jade, dushan jade jade, Southern jade and Canadian jade, among which Xinjiang Hetian jade is a famous specialty in China.

Agate:

From the color point of view: white, gray, red, blue, green, yellow, sheep liver, bile green, chicken blood, black agate and so on. From the pattern, there are: rushes, algae, twisted silk, hawksbill agate and so on. Produced in northeast China, Inner Mongolia, Yunnan and Guangxi. And there is agate with water, called water bile agate.

Stone:

Shoushan stone, serpentine (also known as serpentine jade), turquoise, lapis lazuli, hibiscus stone, woody stone (also known as tiger skin stone), peach blossom stone (also known as golden powder jade), malachite, lapis lazuli, sheep liver stone, tiger eye stone, Dongling stone, etc. Among them, turquoise is a famous product in Yunyang County, Hubei Province, China.

Crystal:

Jewelry made of rock crystal (1 1 piece) includes white crystal, amethyst, topaz, amethyst, red crystal, pink crystal, blue crystal, titanium crystal, ink crystal, ghost crystal, tea crystal (also called cigarette crystal), soft crystal, mane crystal and hair crystal. Produced in all parts of China, including Donghai County, Jiangsu Province, it is rich in crystals.

Emerald:

It has purple, red, gray, yellow and white colors, but green is the most expensive. It is a famous specialty of our neighbor Myanmar.

Coral:

Bonus and white, it is a fossil of coelenterate, produced in Taiwan Province Province, China, with very good quality.

Beads:

Pearls (seawater pearls and freshwater pearls) and cultured pearls (seawater pearls and freshwater pearls).

Editing this paragraph means sapphire.

Hardness: 9

Specific gravity: 4.0 ~ 4. 1

Cleavage: none

Fracture: Shell-shaped to serrated.

A blue corundum is blue because it contains titanium. The crystals are biconical, columnar, tabular or rhombic. Also made into blocks and granules.

Outside, the stripes are white. Transparent to translucent, glass to diamond luster. Genesis: It is formed in some magmatic rocks and metamorphic rocks, and also occurs in sedimentary alluvial deposits.

The chemical composition of sapphire is alumina (Al2O3), which is blue because it contains trace elements of titanium (Ti4+) or iron (Fe2+). It belongs to the tripartite crystal system. Crystal shape is often cylindrical, short column, plate and so on. The geometric shape is mostly granular or dense block. Transparent to translucent, glass luster. Refractive index 1.76- 1.77, birefringence of 0.008, strong dichroism. Not an isotropic body. Sometimes it has a special optical effect-starlight effect. The hardness is 9 and the density is 3.95-4. 1g/cm3. No cleavage, cleavage development. It can produce beautiful starlight under certain conditions, which is called "starlight sapphire".

Quality evaluation:

1. Color: As a kind of colored gems, color is the most important factor in its quality evaluation.

The grading scheme is as follows: cornflower blue (optimal) >; Dark blue (excellent) > bright blue (good) > light blue (medium) > very light blue or blue with gray and green (poor)

2. Quality: The greater the quality, the better. If the comprehensive quality is superior, more than 2 carats is the top grade, and more than 5 carats generally need to talk about the price separately. As far as the existing minimum quality requirements are concerned, the general quality requirements are greater than 0.6 carat, and the high quality can be relaxed to 0.3 carat.

3. Transparency: The more transparent the better. Opaque people are usually useless unless they can show a special Xing Cai effect.

4. Cleanliness: Divided by the benign directional inclusions with Xing Cai effect, the less other bad inclusions, cracks and cleavage, the better.

5. Cutting: The high transparency should be cut into facets, and the low transparency with Xing Cai effect should be cut into cambered surfaces.

6. Special optical effects

Main producing areas: Australia, China, Indian, Sri Lanka, Thailand, Cambodia, Viet Nam and the United States.

Legends and symbols:

Sapphire gives people the impression that the sky is high and the sea is quiet, ethereal and quiet. Orientals have used sapphire as amulet since ancient times, or as a sacred object embedded in sacred objects. In the eyes of westerners, sapphire is a "stone that makes people smart", which symbolizes kindness, honesty, wisdom and noble character.

Ruby ruby

Ruby ruby

Name: In addition to the English ruby name from Latin "ruber" which means red, the English corundum name from Tamil "Kurundam" and Sanskrit "Kuruvinde" means ruby itself. In China, rubies were called "shining in the red palace" and "red elegant aunt" in ancient times.

Category: oxide

Composition: Al2O3 (alumina), which can contain elements such as chromium, iron, titanium, manganese and vanadium.

Hardness: 9

Specific gravity: 4.0 ~ 4. 1

Cleavage: none

Cracked corundum: A kind of conchoidal to serrated corundum with biconical, prismatic, tabular or rhombic crystals. Red, striped white. Transparent to translucent,

Glass to diamond luster.

Genesis: It is formed in magmatic rocks and metamorphic rocks. Because of its high hardness and high density, it is also produced in the gravel layer of river bed.

Quality evaluation:

1. Color: As a kind of colored gems, color is the most important factor in its quality evaluation. The grading scheme is as follows: blood red, pigeon blood red (optimal) > bright red (excellent) > pure red > pink (medium) > purple (poor).

2. Quality: The greater the quality, the better. If the comprehensive quality is superior, more than 2 carats is the top grade, and more than 5 carats is generally subject to another price; As far as the existing minimum quality requirements are concerned, the general quality requirements are greater than 0.6 carat, and the high quality can be relaxed to 0.3 carat.

3. Transparency: The more transparent the better. Opaque people are usually useless unless they can show a special Xing Cai effect.

4. Cleanliness: Divided by the benign directional inclusions with Xing Cai effect, the less other bad inclusions, cracks and cleavage, the better. (perfect > flawless > common amethyst > split with flaws > broken with gaps, which is the gem classification in Diablo)

5. Cutting: The high transparency should be cut into facets, and the low transparency with Xing Cai effect should be cut into cambered surfaces.

6. Special optical effects

Myanmar, Afghanistan, Russian Federation, Pakistan, Tanzania, Australia, Thailand, Viet Nam, Cambodia, Madagascar, China and the United States.

Legends and symbols:

In the Bible, Job said, "Only wisdom is more valuable than rubies"; In some ancient Indian works, ruby is called "the most precious of the twelve gems created by God when he created everything". According to legend, people who wear rubies will "live a long and healthy life, have rich financial resources and have a happy love". "If you wear a red gem ring in your left hand or a ruby brooch in your left hand, you will have a magic power to turn an enemy into a friend".

In fantasy novel and games, rubies are often associated with fire magic. When embedded in weapons, they can also enhance the damage of weapon blades, and when embedded in armor, they can have fire resistance to magic. Red is a symbol of blood, and it also associates ruby with vitality. Ruby (+HP? )。

The spells that use ruby in the third edition of ADND rules include: analysis Dweomer, continuous flame, power cage, simulacra, and time stagnation.

Anyone who has seen El Salvador's trilogy "The Valley of the Ice Wind" will surely remember what the magic pendant of the halfling The Regess is ―― a ruby, of course, with the magic of turning an enemy into a friend.

Diamond diamond

Diamond diamond

Diamonds are gem-grade diamonds. Its English name Diamond comes from the Greek word agonist, meaning "invincible", which accurately reflects the unparalleled hardness of diamonds, so this name has been used since the middle of16th century.

Category: Natural Elements

Component: c

Hardness: 10

Specific gravity: 3.52

Cleavage: complete octahedral fracture: shell-shaped.

Crystallization characteristics: equiaxed crystal system, octahedron, rhombic dodecahedron and cubic crystal form are common, and stepped growth lines, growth cones or etched images often develop on the crystal surface.

Genesis: It often occurs in kimberlite (breccia mica peridotite) of ultrabasic rocks and in rock pipes.

Luminous characteristics: blue, yellow, orange and pink with weak intensity under ultraviolet fluorescence have long and weak short wave; After being irradiated in the sun, it can emit light cyan phosphorescence at night; Under X-ray, most of them are blue or light blue fluorescence, and a few have no fluorescence, while under cathode ray, they are blue or green.

Quality evaluation principle: 4C classification principle, namely color, cleanliness, cut and quality. However, this classification principle is only applicable to the quality evaluation of colorless series diamonds, not to the evaluation of colored diamonds and various optimized diamonds.

Origin:

/kloc-Before the 0/9th century, India was the only diamond producing area in the world. At that time, the main mining was diamond placer impacted by rivers. South Africa has played an extremely important role in the world diamond market since the discovery of the primary kimberlite type diamond mine. With the discovery of a new type of K-Mg lamprophyre, Australia's diamond production jumped to the top in the world. Diamonds produced in Siberia are also in the leading position.

In addition to the above-mentioned concentrated diamond producing areas, Brazil, Venezuela and Guyana in South America and Indonesia, China, Liaoning, Shandong, Hunan and Guizhou in Asia also have certain diamond production.

Related legends and symbolic meanings:

At one time, people thought diamonds came from Tianshui or dew. In Sanskrit, the word diamond means lightning, which expresses the belief that diamonds are born of lightning. Before the Renaissance, the highest temperature that humans could reach with fire could not hurt diamonds. The legend of indestructible diamonds goes straight to the beginning of European diamond cutting and grinding industry in16th century. For hundreds of years, people have held the idea that diamonds are indestructible, so the wearer will not be destroyed, which also makes diamonds sell well in the era of disease. During this period, most legends hinted at the benefits of owning diamonds, such as victory, strength, courage, power, wealth, eternal life, happiness, friendship, avoiding evil, staying young forever and realizing dreams. Some even say that diamonds can make people invisible and bring the dead back to life.

17 and 18 centuries, with the gradual popularization of diamonds, the legends of plague and witchcraft gradually faded, and people's worship of their divine power gradually turned into symbols and psychological associations. Princes and nobles in almost every country have had legendary experiences related to diamonds, and diamonds have become a symbol of power. 1700 years ago, diamonds were almost all owned by the royal family, and their image could not be separated from the royal atmosphere. During the period of 1948, De Beers adopted the slogan of "Diamonds Forever" to promote engagement diamond rings and wedding anniversary rings as a symbol of love and to express continuous commitment. Love is the biggest reason why people buy diamonds at present.

Major diamond cutting and grinding centers:

Antwerp, Tel Aviv, Mumbai and new york, USA.

In fantasy novels and games:

Besides being a precious gem with high value, as a sorcerer's stone, soldiers and magicians regard the hardness of diamonds as an invincible symbol, while fortune tellers and poets call it the unfathomable mystery of human life. Diamonds often become sacred stones for undead monsters. The amulet inlaid with diamonds can defend against death spells, the attack power of weapons and the damage to undead monsters are enhanced, and the protection of armor against undead attacks is enhanced (in Diablo, the diamond shield card can increase all the resistance of the holder). A diamond or enough diamond powder is an essential magic material when casting a spell to bring people back to life. In the third edition of ADND Rules, diamonds are used in the following spells: Guardian Inscription, Guardian Inscription, Star Rain, Non-detection, Spell Protection, Resurrection, Resurrection, Stone Skin, Syol, Temporary Stagnation and Real Resurrection.

Add two points:

Diamonds are the fastest conductive materials in the world. If your CPU has a diamond radiator, then … you must be crazy.

Among natural materials, diamond is the hardest. The artificial material graphene is harder than diamond.

emerald

Emerald is also one of the precious gems recognized by the international jewelry industry. Because of its unique green color, unique charm and magical legend, it is deeply favored by westerners and more and more loved by China people.

The color of emeralds is very charming. Some people use spinach green, onion heart green and tender tree bud green to describe it, but they can't accurately express its color. The green is a little yellow, but it seems a little blue, and even the spectrum seems to be a little less wavelength. Indeed, no natural color can make the eyes so comfortable. Whenever you stare at the green lawn and leaves, the pleasing feeling can be imagined, but it is not as good as the color of jade. It is one of the treasures that people can never get tired of seeing. Whether it is cloudy or sunny, whether it is under artificial light or natural light, it always emits soft and rich light. This is the charm of emerald, king of emeralds.

Beryllite is produced in nature, and its main component is Be3Al2[Si6O 18], which is a hexagonal beryllium aluminum silicate mineral. Emerald is formed because it contains a proper amount of Cr2O3(0. 15~0.6%). It is the most outstanding member of beryl family.

Emerald is the birthstone of May, symbolizing luck and happiness. Wearing it will bring peace to people's life. This is also the 55th wedding anniversary stone.

Shoushan stone

Shoushan Stone Shoushan Stone, one of the traditional "Four Yin Zhangshi" in China, is known as the "Chinese treasure". Shoushan stone is distributed in the "golden triangle" zone at the junction of northern suburb of Fuzhou and Lianjiang and Luoyuan. Shoushan stone belongs to the rock subclass of colored stone in gemology and color stone science. Its species and stone names are very complicated, with about 100 varieties.

The formation of Shoushan stone

Shoushan stone deposit is distributed in the mountains and streams around Shoushan Village in the northern suburb of Fuzhou City, Fujian Province, with Qishan in the west, Lianjiang County in the east, Dunyang in the north and Yueyang in the south, covering an area of about 10 km in Fiona Fang. Shoushan stone belongs to pyrophyllite deposit with volcanic hydrothermal metasomatism (filling). According to geological research, volcanic rocks (pyroclastic rocks) were formed in Jurassic period10.40 billion years ago, which is the product of volcanic eruption. Later, during or after volcanic eruption, accompanied by a large number of acidic gases and hydrothermal activities, feldspar minerals in surrounding rocks were metasomatism and decomposition, and impurities such as K, Na, Ca, Mg and Fe were leached out. However, under certain physical conditions, the remaining stable elements such as al and Si are either recrystallized and mineralized, or Al and Si sols dissolved from rocks are precipitated and crystallized along the cracks of surrounding rocks to form mineralization. The mineral composition of the ore is pyrophyllite, followed by Yingshi, diaspore and kaolinite, with a small amount of pyrite.

Composition of Shoushan stone

Shoushan stone is a single mineral or multi-mineral heterogeneous aggregate with pyrophyllite, dickite, kaolinite, nacrite and illite as the main clay minerals, and contains a small amount of syenite, sericite, diaspore, chlorite, andalusite, epidote and pyrite. Shoushan stone is divided into pyrophyllite type, kaolinite group type and illite type according to its main mineral composition, and pyrophyllite type is the main mineral composition; The main mineral components of kaolinite formation are kaolinite, dickite and nacrite. The main mineral composition of illite type is illite. According to geological survey data, the main trace elements of Shoushan Stone are tin, molybdenum, lead, zinc, copper, chromium, nickel, cobalt, vanadium, barium, gallium, scandium, niobium, yttrium and beryllium. At least seven of them (molybdenum, zinc, copper, chromium, nickel, cobalt and vanadium) are essential trace elements for human body. There is an essential trace element (Sn) as a candidate.

Characteristics of Shoushan Stone

Shoushan stone is crystal clear, moist, transparent, colorful and moderate in hardness. It is "fine, condensed, greasy, moist, spiritual and transparent" in Liu De. Its crystalline state belongs to aphanitic aggregate, showing Mohs hardness such as fine grain structure, micro-scale metamorphic structure and residual tuff structure: pyrophyllite type 1.0 ~ 2.5 degrees, kaolinite type 2.5 ~ 3.5 degrees and illite type 2 ~ 3 degrees. Density: pyrophyllite type 2.80 ~ 2.85, kaolinite type 2.55 ~ 2.65, illite type 2.7 ~ 2.80. Stone is rich in color, including red, yellow, green, orange, purple, brown, brown, black, white, milky white, purple-red, brown-yellow, purple-black, colorless and transparent. The color trend is dark and unpredictable, and it is often composed of many colors. Waxy luster, earthy luster, a little oily luster. Most of them are opaque to slightly transparent, and some are almost transparent. It is often a dense block structure, a breccia structure, a grain structure, and a special flocculent and grain structure, such as "radish grain". High toughness, suitable for carving.

black agate

English name black agate black agate. Mainly because agate contains more organic matter. Pure black agate is rare in nature, and its depth varies with the uneven content of organic matter. Pure black agate sold in the market is mostly the product of artificial dyeing or used as other stones.

Black agate symbolizes perseverance. We use the sentences in the Bible to interpret these beautiful dark stones-love is as strong as death, and there is perseverance beyond everything in silence. Legend has it that using the energy of black agate can remove impurities in the gas field, thus effectively stimulating its own charm. People who wear black agate may not have extraordinary beauty and wisdom, and may not have natural affinity and good popularity, but the inherent "edges and corners" in their personality are fatal temptations.

Black is stable, solemn, eternal, classic, charming, noble and mysterious, representing the characteristics of low-key, implicative and introverted. Black is also a strong voice, which embodies a powerful force that no one can resist. Black represents the arrogance behind introversion; Resistance to control; Exaggerated rendering and minimalism; All kinds of opposites can reflect complex multiple rays through black, forming irreplaceable perfection.

opal

Opal is a kind of gem. Opal is a commercial name, its mineralogical name is Opal, and its transliteration is Opal. . According to the different basic colors, opal can be divided into white opal, black opal and fire opal.

Baioupo

The basic colors of white opal are: transparent and colorless, protein color, light gray, light yellow, light blue, light gray, light blue and so on. After being polished into a hemispherical gem, the surface will appear colorful. The background color is white, and the brightly colored white opal is the best.

Black opal

Black opal is rare in output and is the most precious variety among opal gems. The basic color is black, including dark green, dark blue, dark gray, brown and other colors, with black as the best.

Fire opal

Fire opal can be divided into colored and colorless, from translucent to fully transparent, and the color ranges from yellow to orange red. Among opal gems, fire opal is the lowest grade, and the price is far lower than the first two categories.

Edit this paragraph identifier

The identification of ruby bracelets can generally be divided into two categories: original stone and finished product.

The identification of the original stone can be divided into field identification and indoor identification. In the field identification, most simple tools such as magnifying glass and knife are used to preliminarily name gem minerals. Indoor identification mainly uses various means and instruments to further determine the data of gem minerals, which provides an important basis for gem identification.

For the identification of finished gemstones, it is necessary to identify the tested gemstones without destroying the integrity of the gemstones.

Commonly used and easy to master gem identification instruments are as follows:

1. Pen spotlight flashlight: used to observe the transparency of dark gemstones. Beads of spotlight flashlight should be concave in the writing surface, not protruding from the writing surface, otherwise it is not easy to observe.

2. Magnifier: It is one of the instruments for magnifying and observing gems. The most commonly used magnifying glass is 10 times, and there are several kinds of magnifying glasses with 20 or 30 times. Magnifier is a key tool and necessary thing for gemologists, and it is easy to carry. It can be used to identify the variety and authenticity of precious stones. With a magnifying glass, we can observe: (1) the surface damage, scratches and flaws of the gem. (2) Cutting quality. (3) Polishing quality. (4) Defects and inclusions in gems. (5) color distribution and growth line. During identification, the gem should be placed under strong light about 2.5 cm away from 10 times the magnifying glass, and the distance should be adjusted slowly until it is clear. It is also important to choose the quality of the magnifying glass. Poor quality amplification will produce graphic distortion.

3. Dichroic mirror: Some gems are multicolored, and the best instrument to observe the multicolor of gems is the dichroic mirror. Dichroic mirror is a kind of optical instrument with reasonable structure, low price, compact and simple. The dichroic mirror uses a suitable transparent colorless calcite (Iceland spar) diamond. Because Iceland spar has high birefringence, the instrument can separate two plane polarized light rays passing through the gem. It is required that single crystal gemstones with transparent colors can detect polychromatic colors, while jadeite cannot detect polychromatic colors. Dichroic mirror is mainly used to distinguish ruby from spinel and red-purple tooth black; Distinguish blue spinel from blue tourmaline; Distinguish sapphire from blue synthetic spinel. When detecting a gem with a dichroic mirror, you must keep turning the gem until the two colors with the biggest difference appear on the window. For the determination of trichromaticity of gemstones, we must carefully and repeatedly test. Seen from three different directions, three colors seem to be three colors. Note during testing: the distance between eyes, dichroic mirror and gem sample should not exceed 2-5mm.

4. Refractometer: Refractive index is an important optical constant of transparent gemstones and the main basis for identifying gemstones. There are two main methods to measure refractive index: one is direct measurement and the other is refractometer measurement; The other is relative measurement, which cannot be immersed in liquid. Refractometer is made according to the principle of total reflection of light. The commonly used refractometer is only suitable for gems with refractive index of 1.36- 1. 1. The calculation method of the refractive index (n) of gemstones is that the ratio of the propagation speed of light in air (V 1) to that in gemstones (V2) is a constant, that is, N=V 1 /V2. An isotropic gem in which light propagates with constant propagation speed and equal refractive index is called single refractive index. Anisotropic gemstones have two readings in the refractometer, and the difference between the maximum and minimum refractive index values is called birefringence. Refractometer is one of the most commonly used instruments for gemologists. It is small in size and convenient to use. He can not only measure the refractive index of faceted gemstones, but also measure the refractive index of globoidal gemstones through point measurement.

5. Charles color filter: The color filter is designed by using the specific wavelength of absorbed light. It consists of two gelatin filters that only let dark red and yellow-green light pass through, and it is a gem identification instrument. The color filter is small in size, light in weight, and easy to carry, which is particularly effective in identifying some dyed gems and artificial gem, and is very effective in identifying colored jadeite. It can distinguish emeralds from other imitations, and it must be comprehensively considered by other methods in order to judge accurately. Emerald appears red or pink under the color filter, while other natural green gems similar to emerald do not appear red under the color filter.

6. Gem microscope: an important tool for magnifying and observing gems. It can detect the external and internal features of gems, which can not be clearly confirmed or observed with a magnifying glass 10 times. Gem microscope can observe the inclusions, cleavage, twin lines, growth lines and color bands inside the gem; Observe the grinding, polishing degree and accidental damage of gems; Distinguish between two-layer stones and three-layer stones that assemble gems. Gem microscope has reasonable structure, complete auxiliary equipment and large variable magnification, which is generally 10 to 70 times. Gem microscope has two kinds of light sources. Generally, the bottom lamp is used to observe the internal defects of gems, such as inclusions and cracks. Observe the surface features of gems, such as cracks, bands and cleavage planes. , with reflective lights. Gem microscope is a precision instrument and should be used in strict accordance with the operating procedures.

7. Thermal conductivity meter: Thermal conductivity meter is designed and manufactured according to the good thermal conductivity of diamond. Most gems have no or very low thermal conductivity, so the general thermal conductivity meter is designed to distinguish diamonds from artificial imitation diamond products, and it is a special instrument to distinguish diamonds from other imitation diamond products. The diamond thermal conductivity meter consists of a metal probe and a control box. When the tip of the probe touches the diamond surface, the temperature drops obviously, and the measurement results are displayed by the chirp sound on the signal lamp or the instrument head. The thermal conductivity meter is more than ten centimeters long and easy to carry and use.

8. Polarizer: It is a simple optical instrument. Its principle is that plane polarized light intersects vertically and light cannot pass through. The polarizer consists of two polarizers with vertical vibration directions, a bracket and a bottom lamp. Used to detect the brightness (isotropic or anisotropic) and multicolor of gemstones. Turn on the polarizer of the lighting lamp and observe the light and shade changes of the gem sample.

(1) If the sample is bright, it may be aphanitic or microcrystalline aggregate, such as chalcedony and jadeite.

(2) If the sample is completely black and there is no change in light and shade, continue to observe from another angle; If there is still no change in light and shade, the sample belongs to isotropic body. Gems belonging to isotropic bodies are equiaxed and amorphous.

(3) If the gem is rotated by 360, the brightness of the gem sample changes four times, indicating that the sample is not isotropic. Gems belonging to anisotropic bodies include tetragonal, hexagonal, triangular, rhombic, monoclinic and triclinic crystals.

(4) If the sample rotates under orthogonal polarization, dark serpentine, grid or irregular shape can be seen, which may be the abnormal interference color of isotropic gemstones, so we should attach great importance to it at this time. Using polarizer, we can also detect the multicolor color of gemstones and verify the heterogeneity and homogeneity of gemstones.

In addition, commonly used gem identification instruments include absorption spectrometer, fluorescent lamp, X-ray diffractometer, electron probe and so on.

The difference between gem and jade

There are always people who can't tell the difference between emeralds and emeralds, because they are both transparent and have a charming green luster. In fact, jadeite and hetian jade belong to two completely different categories: jadeite belongs to precious stones and jadeite belongs to jade. So, what's the difference between gemstones and jadeite? Generally speaking, gems are made of natural single crystal minerals, that is to say, a gem is usually made of single crystal, and the crystal is visible to our naked eyes (so it is also called crystal). Gemstones are usually transparent. After the light enters the cut gemstone, we can see the flash of gemstones, such as rubies, sapphires and emeralds, after a series of reflections and refractions. There are also a few gems that are natural single mineral aggregates, such as opal and lapis lazuli, and some organic substances, such as amber, pearl, coral and ivory, which are also included in the broad sense of gems. They are also called biological gems. Jade is another concept. It consists of countless tiny crystals that we can't see with the naked eye. Its structure can only be seen clearly under a high-power electron microscope, so people call jade an aphanitic mineral. Broadly speaking, the aggregate of these tiny crystals can be called jade. Usually people talk about jade, mainly referring to Hetian jade (white is the typical color) and jadeite (green is the typical color), which are internationally recognized as relatively valuable jade. Gemstones are usually transparent. Because the surface is extremely smooth, the gem surface has a strong ability to reflect light. Light can enter the gem, be reflected and refracted, and then leave the gem to reach our eyes. Therefore, the high-purity cut gemstones we see generally glow. Because jadeite is composed of countless tiny crystals, there are always gaps between them, so it is impossible for the master of processing to smooth the surface of the gem. The trajectory of light on the jade surface is like sunlight shining on a wavy lake. This effect is also called diffuse reflection. If you are interested in comparing the surface gloss, you can take a closer look at the difference between your own window glass and frosted glass in the shower room. Is the gloss smoother and stronger? Therefore, the jade surface we usually see is moist or oily. Because light rarely penetrates gems, we usually think jade is translucent. Of course there are exceptions. Top jadeite can also be almost transparent.