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What's the difference between jade and crystal?

What's the difference between jade and crystal? Crystal is a colorless and transparent large-scale timely crystal mineral. Its main chemical composition is silicon dioxide, which is a substance that "comes out of the uterus" with ordinary sand. When the silicon dioxide crystal is perfect, it is a crystal; After gelatinization and dehydration, silicon dioxide is primary crystal mineral, blonde crystal variety brain; Water-containing silica gel becomes opal after solidification; When the particle size of silica is less than several microns, chalcedony, flint and secondary quartzite are formed.

Jade can be divided into nephrite and jadeite. Nephrite generally refers to white jade, sapphire, jasper and northeast jade produced in Xinjiang, and jadeite refers to jadeite produced in Myanmar. Whether nephrite or jadeite, their texture is very hard and their colors are very bright, so they are known as "the king in the stone".

What do you think about the difference between crystal painting and ice crystal painting? Who can tell me the difference between frameless crystal painting and ice crystal painting in more detail …

The difference between diamond and crystal crystal is a member of the seasonal family and one of the most common minerals. Usually formed in igneous rocks, metamorphic rocks and sedimentary rocks, the chemical formula is Sio2, and the Mohs hardness is 7. The end of the crystal is rhombohedral or pyramid-shaped, and the crystal face is usually striped and glassy, with rich inclusions. Generally speaking, the purer the color, the brighter the crystal, the higher the clarity and refractive index, and the higher its value. The main component of diamond is carbon (C), and the carbon content is 96%-99.9%. Even pure diamonds contain 0.00 1% impurities. Impurities in diamond include silicon, aluminum, calcium, magnesium, manganese, titanium, chromium, nitrogen and so on. Except N, other impurities usually exist in the form of mineral inclusions, and diamonds often contain mineral inclusions such as magnetite, ilmenite, garnet, chrome diopside, olivine and graphite. First of all, diamond is one of the hardest stones known, so we can know it simply by carving corundum with diamond. Oiliness test: Draw a line on the diamond table with a special pen or ballpoint pen dipped in oily ink, and an uninterrupted straight line will be left. However, other imitations are not lipophilic, leaving intermittent dotted lines at the scribe line. Water drop test: the water drops on the diamond will remain spherical for a long time, while the water drops on the imitation will disperse in a short time. Breathing test: breathe into the diamond, if the water vapor on the diamond disappears, it will become a real diamond immediately; If the water vapor stays on the diamond for a few seconds and then disappears, it is a fake diamond. Sensory test: Touch a diamond and its imitation with your tongue at room temperature. The diamond is much cooler than the imitation. There is a very simple and good identification method, that is, put it on a piece of wired paper and put it upside down to see if you can see the line through it. If it can be copied, natural diamonds can't be seen. This method is very simple. It is simpler and more scientific to use "diamond pen (also called heat conductor)" to distinguish. Crystal is anisotropic, while glass is isotropic, which can be effectively distinguished by a simple double polarizer. But now few people use glass to imitate crystals, and more are synthetic crystals. The way to distinguish synthetic crystals from rock crystals is that synthetic crystals have "crystal nuclei (a kind of flaky longitudinal inclusions)", while rock crystals do not. In addition, the uniform color of synthetic crystals and monotonous inclusion types are also different methods from rock crystals.

The difference between a gem and a crystal is that there is no red crystal. The so-called red crystal means that the inclusions are red but not brilliant red. Because it is iron, it is rust red, and there is no transparent red crystal. Ruby and crystal can be distinguished at a glance as long as they have seen the real thing once, and their colors, textures and luster are different.

Ruby will be similar to some other semi-precious stones, but it will never be confused with crystal stone.

Generally, zircon, garnet, tourmaline, spinel and glass can be confused. . .

What's the difference between artificial crystal and rock crystal? Artificial crystals and rock crystals are both made of silica, and high-purity silica is called "crystal". Crystal is a transparent timely crystal, which is a hexagonal columnar crystal. It has high hardness and strong reflectivity. Pure crystals are colorless and transparent crystals, which can hardly be found in rock crystals without impurities. Most rock crystals contain bubbles, impurities and crystals are mixed. Artificial crystal is made of quartz sand through a series of processes, fine cutting technology and flawless polishing. The crystal is pure and transparent, which makes up for the deficiency of rock crystal. Adding metal elements such as lead to artificial crystals can enhance the splitting of light and show the nobility of crystals. Due to the complex technology and superb technology, some artificial crystals are even more expensive than those in rock crystals

Fuheng lighting, the leader of crystal lamp

The difference between calcite and crystal is difficult to describe to you because calcite has many crystal forms.

There are all kinds.

Moreover, crystals are generally long columns, and calcite can't grow.

What's the difference between pure natural crystal and jade? Identification of true and false jade articles

Jade can be divided into nephrite and jadeite, also known as jadeite. From the chemical composition, nephrite is a silicate containing calcium, magnesium and iron, while jadeite is a silicate containing sodium and aluminum.

Here are several common methods to identify true and false jade articles:

Identification method of (1) water

Drop a drop of water on the jade. If it becomes dew, it will be real jade if it persists for a long time.

(2) Touch by hand

If it is real jade, it feels cold and lubricated by hand.

(3) Observation method

Looking at jade under the light, it is a real jade with clear color and even green distribution.

(4) tip identification method

The real jade on the tip of the tongue is astringent, but the fake jade is not.

In addition, you can also observe with a magnifying glass, mainly to see if there are cracks, and the value of cracks is greatly reduced.

Jade quality appraisal

There are six criteria to identify the quality of jade, namely "color, transparency, uniformity, shape, percussion and luster".

(1) color

Green is the best jade, and the value of red and purple jade is only 1/5 of green jade. If jade contains red, purple, green and white, it is called "Fulu Xi Shou"; If it only contains red, green and white, it is "Fu Lushou". The dull and yellow ones are inferior. If it is monochrome jade, the color is better.

(2) Pass

Transparent and crystal clear as glass, no dirty spots, no chaff and no astringency is the top grade. Translucent and opaque jade are called intermediate jade and ordinary jade respectively. Before and during the Qing Dynasty, jade with red, green and white colors was called jadeite. In modern times, jadeite refers to generally transparent jade. At present, jadeite is transparent and green.

(3) uniforms

The color of jade is uniform. Although it contains white and green, the color is uneven, so the value is very low.

(4) Shape

The shape of jade can be processed into different styles according to different aesthetic requirements, and there is no special standard. Generally speaking, the bigger the jade, the better.

(5) Knock on the door

Jadeite often has cracks and cuts, which are generally not easy to observe. If you knock with a metal bar or gently throw jade on the counter, you can tell whether there is a crack from the clear voice. The louder, the better.

(6) according to

Emerald has black spots and flaws that are not easy to find with the naked eye. As long as you take pictures with a magnifying glass of 10 times, you can have a panoramic view.

The quality of jade can be divided into 10 grades, and each grade can be subdivided into three grades: upper, middle and lower. Among them, white jade has the lowest value regardless of color and transparency.

Natural jadeite is characterized by slight light color, without light blue (commonly known as evil color). There is also a synthetic jade, which is made of jade powder, crystal and salt water, and looks like a dark "old pit jade". The identification method is very simple, because it is different from natural jade in proportion. It can be said by hand or with a balance, and the heaviest one is the real jade.

At present, some exquisite fake jade is often mixed in the market. The general methods to identify fake jade are watching, listening and testing.

(1) Look

Mainly depends on the crystal transparency, internal structure, luster and so on. Real jade is transparent, oily and shiny, with natural patterns, and the internal fiber state is not easy to imitate.

2. Listen

Real jade sounds crisp, while fake jade sounds dull.

(3) measurement

Mainly to measure hardness. With the glass plate (friction hardness of 5.5) as the standard, except jadeite and turquoise, stripes can generally be drawn on the glass plate, and jadeite itself is complete. Fake jade is generally soft and can't scrape the glass.

Common fake jade is generally made of plastic and glass. They are all amorphous materials with low hardness and low density, and they are also the essential characteristics of materials. Plastic, for example, can be picked with a steel needle or floated gently in your hand. Glass is bubble-like under light or sunlight, and amorphous under polarizer (there is no periodic change of light and shade when rotating), and there are raw materials for making spiral stripes.

Quality identification of jadeite jade

Among many members of the jade family, jade is the most precious. It is a natural ore with extremely high hardness and little output. Its colors are mainly green and red. Red is scarlet and green is emerald, hence the name jade.

Classification of (1) jadeite

(1) Super grade: bright green (emerald), apple green, glass floor (translucent, fine texture), even and bright, without impurities and cracks.

Commodity grade: green, oily green land, slightly transparent, translucent grandmother green veinlets and mottled green.

③ Ordinary grade: lotus root powder mill, bean green, light green, fine white and slightly transparent. Opaque jadeite is generally only used as jade ornaments.

(2) Quality identification of jadeite jade

1 texture. Natural jadeite is transparent or translucent in texture, and its surface is bright and shiny. If you look closely, you can see the nearly round and slightly transparent "salt particles" and the fibrous substances around them.

② Hardness. Natural jadeite is jadeite, and its Mohs hardness is 7 degrees. It will be carved by a sharp knife without leaving any trace. The hardness of fake jade is low, so a sharp knife can draw it out.

3 Emerald. When natural jadeite is observed under strong light, emeralds with other mineral particles can be seen, which are called Cui Hua or emeralds. Fakes made of glass, plastic and porcelain have no such "emerald" characteristics.

④ Relative density (specific gravity). Natural jadeite has a hard and dense structure, no bubbles, high density, and clear sound when knocking; Fake products have loose structure or bubbles, low density and hoarse knocking sound.

⑤ color. The real product is rich and pure emerald color. Some fakes are made of white jade, serpentine, Australian jade, Han Guoyu, marble and even various stones. After decoloring, it is filled with high-hardness plastic slurry and colored, or soaked in green liquid to make "colorful jade". Observing under strong light, you can see green lines, which are messy and small; Some do not show lines, but they are not clear, with poor gloss and lighter weight than the real thing.

Put the fake into the melted wax liquid, and the injected pigment will slowly separate out. In this way, the detected sample will not be destroyed, and the authenticity can also be identified.

Celsi filter observation, the added emerald is purple under the mirror, and the natural genuine color remains unchanged.

Some fake jadeites are artificially melted by glass, with loose structure, uniform and dark green color, some with bubbles, and hoarse when struck with hard instruments.

(3) the choice of jadeite

1 Look at the color. See if the color is pure, rich and uniform, and use a spotlight flashlight to check whether there are hidden variegated colors. Rich, pure and uniform color, less impurities. Emerald green has a higher price, followed by red and purple. Among the greens, Mabel Miao, which is tender and yellowish, is the best, followed by ruby green, river green and oil green, and the green is evenly distributed.

② Observe the transparency. Observing under strong light, the higher the transparency, the better.

3 Listen to the sound. The knock on the door is crisp and pleasant.

④ Observe emeralds and stone flowers. According to light observation, jadeite has the flash of other mineral particles (namely emerald), and there are often massive white flowers called stone flowers. Both of them get twice the result with half the effort.

⑤ Look at cracks and dark spots. Some cracks exist in the raw ore, and some are caused by processing, so the less the better; Black spots are everywhere in jadeite, so it is better to have fewer and smaller ones.

⑥ Look at the processing level. Smooth surface, good polishing and good shape are preferred.

How to distinguish real agate from fake agate?

The most striking sign that natural agate is different from fake agate is that its cross section has concentric layered structure. With this logo, the whole agate is easier to identify, and the cut finished product is easy to admit mistakes because there is no neat and obvious pattern. But generally speaking, natural agate feels cool, its surface looks like a layer of wax, and it has the luster of wax, translucency and hardness of Mohs 7, so it can't be carved with a knife, because the crystals formed in the molten state are mostly spherical, so it is particularly dense; After polishing, the surface is more delicate. After rubbing on the hard miscellaneous board for more than ten times, the agate was not scalded, but the board was scalded. Colors are often mixed together to form beautiful patterns, layers, tapestries and other colorful patterns.

In addition to artificial synthesis, some fake agates are made of high-quality stones. Its basic characteristics are: it feels cool, but it has no waxy feeling and luster, and some of it has low hardness and can be carved with a knife; Breaking the observation section, except agate has a layered feeling, the particles are thicker and even cracked; Opaque, with clear boundaries between colors. Some unscrupulous traders stick a thin layer of organic matter on the surface of fake agate, giving people the illusion of wax-like luster and feel, so special attention should be paid to identification. The acceptance rate of missing good answers is 36.1%2010-1-3017: 28. The simple way to report is:

Look at the color first. Color is the most important factor to evaluate the quality of jade. Jade with uniform color, sunshine, massiness and integrity is the top grade. "Unity" means unity; "Yang" means bright colors, giving people a cheerful and non-stagnant feeling; "Thick" means dark color; "Positive" means that no other variegated colors are mixed together.

The second is to look at the texture. Emerald is a polycrystalline mineral formed by silicate at high temperature and high pressure, and the size of its constituent crystals will directly affect the smoothness, transparency and color tone after polishing. Therefore, the finer the polycrystalline structure, the better the texture of jade.

The third is transparency. Transparency is a physical phenomenon that complements texture. The finer the texture, the higher the transparency. If the permeability of jade is like glass, the fineness of the crystal inside can make the light pass through without being blocked.

The fourth is to look at the handling of the day after tomorrow. Jade is mined, just like ore. It must be carefully cut into different shapes by experienced professional craftsmen, and then processed, polished and carved, polished and waxed before it can be sold in the market. Those that are not bleached or dyed at all during the processing are "A" and have the highest value; Bleaching and fading are "B" grade, followed by value; The value of dyeing grade "C" is low. Excellent acquired processing can make jade icing on the cake and double its value.

Fifth, look at the cracks. Cracks in jadeite may be caused during mining or processing. With cracks, no matter how good the color, texture and transparency are, it will affect its value. Sometimes cracks are not obvious on its surface, but they can be seen by careful observation in the sun. Especially for bleached or dyed jade, cracks are a common phenomenon.

While distinguishing the quality of jade, we should also prevent artificial imitation of jade from confusing the real with the fake. Artificial imitation jade is made of glass, plastic and other materials after dyeing. Glass imitation jade mostly contains bubbles, and the color is bright, and green has a strong light, which is different from real jade. Plastic imitation jade is lighter than real jade, with poor transparency and dim tone, which is far from real jade.

Here are the advantages and disadvantages of jadeite, and the methods to distinguish between true and false:

Water identification method drops a drop of water on jade, and if it becomes dew, it is real jade; The water droplets disappear quickly, which is a fake.

Touch it with your hands. If it is real jade, it will feel cold and lubricated.

In the inspection method, jade objects face bright places, such as sunlight and lights. If the color is clear and the green is evenly distributed, it is a real jade.

The tongue licking method has a astringent feeling on the tip of the tongue; Fake jade has no astringency.

Magnifier Watch the purchased jadeite under the magnifying glass, mainly to see if there are cracks. The jade without cracks is the best quality, followed by cracks. Even if it is real jade, the value of cracks is greatly reduced. The more cracks, the more obvious and the lower the value. (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 natural noodles 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.

(Check with hair: If the crystal is placed on the hair, then the rock crystal is the kind that the human eye can see the double shadow of the hair through the 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.

Artificial crystal is also called "synthetic crystal", and the original stone has no hexagonal crystal system, which is the easiest place to judge; But if it is ground into a finished product, it is not easy to distinguish it by the above method, and it is necessary to use an "ultraviolet spectrometer" to distinguish between true and false.

Attached:

At present, there is no strict grading standard for crystals in the world, and different markets have different definitions. The following is an industry agreement that is not strict. Identification is based on the results of naked eye observation, without the help of a magnifying glass, mainly for white crystals, with the following levels:

AAA grade: The whole crystal is transparent and flawless inside and outside, and the surface has no artificial defects visible to the naked eye.

AA level: there are tiny flaws, or tiny natural inclusions, clouds or flocs not exceeding 3mm.

Grade A: There are slight flaws, and clouds or cotton wool can be easily seen by naked eyes.

Class AB: There are big cloud inclusions, small ice cracks and small scratches on the surface.

Grade B: More than half of the whole crystal is cloud-like and inclusion, with large ice cracks and small cracks on the surface.

Grade C: the lowest grade, with cloud-like shape as a whole, obvious ice crack marks and obvious cracks on the surface, which seems to break at any time.

Finally, I remind you that finding a professional store is the most secure. Roadside vendors and vendors are not professional enough and easy to run. Even the counters in department stores are unprofessional, and crystal and crystal glass are often confused, which makes people afraid to make mistakes. Appreciate special optical effects. If the crystals are wrapped in cracks and air, some will form a "rainbow" under the light. For example, there is a heart-shaped rainbow on the left side of the Emerald Hills. Some mineral inclusions in crystals have bright metallic luster, and the most common ones are all kinds of hair crystals, among which golden hair crystals are the most eye-catching; The hair crystals in some crystals are arranged in a special pattern, and the starlight effect of cat's eye effect can also appear after polishing. For many crystal lovers at present, it is worth mentioning that a good crystal ornamental stone is a work of art of nature. Instead of buying a pile of cheap garbage, it is better to buy an expensive boutique, because "boutique" not only has high appreciation and collection value, but also has high "energy" Owning a boutique can even give you a sense of pride. Whether you can get high-quality goods or not is related to your luck, knowledge, cultivation and vision. Before buying a crystal, you should read it carefully, because different people or watching the same crystal at different times can have different discoveries, feelings and inspirations, and the value of a crystal can be reflected to some extent through people's discovery and understanding of its content. ......

What's the difference between crystal and garnet? What kind of garnet belongs to a kind of crystal? (Of course, this refers to the real thing. )

Crystal is the general name of artificial crystal and rock crystal, and there is no comparability ~

What's the difference between jadeite and precious stones? Precious jade in a narrow sense refers to the geological causes and value factors of precious stones or jade itself. It refers to the remains of minerals, rocks or paleontology formed by geological processes, which have excellent arts and crafts characteristics, are rare, durable and of high value, and can be processed into various exquisite jewelry and valuable handicrafts. Gem refers to a mineral single crystal or a part of it which is formed by geological processes in nature and endowed with rarity. It is extremely rare, magnificent, colorful, hard and durable, and can be used for people to make exquisite jewelry and handicrafts. Most of them are crystal elements (such as diamond-diamond) or compounds (such as corundum-red and sapphire). Jade refers to transparent or opaque minerals or rocks formed by geological processes in nature, with fine geology, clean color, toughness and wear resistance, and produced in dense blocks. It is an important part of rock and mineral resources. Like other useful minerals and rocks, it is formed by the geological action of various elements and their compounds that make up the earth's crust. It can not only form an independent deposit, but also coexist with other mineral resources in the form of symbiosis. After polishing, jade presents the characteristics of delicate, soft, clean, solid and greasy polished surface, which is different from the dazzling, flashing and gorgeous gemstones. Such as nephrite, sole jade, plum blossom jade, etc. At present, nearly 3000 kinds of minerals and mineral aggregates have been found in nature. Among them, there are about 230 kinds of minerals and their aggregates that can be used as gems, and only 30 kinds of common gem raw materials. Its chemical components are natural elements, oxides, hydroxides, silicates and phosphates. Common gems are diamond (diamond), ruby (corundum), sapphire (corundum) and emerald (beryl). Opal (golden emerald), aquamarine, crystal, amethyst, tourmaline (tourmaline), ruby (spinel), Turkish jade (turquoise), olivine, pink jade (andalusite), malachite, soft amethyst (fluorite), jadeite (jadeite), hetian jade (nephrite) and jadeite. Specifically, Shoushan stone, Balin stone and Qingtian stone can all be classified as jade. View original post >>

How to distinguish between crystal jade and crystal stone? The identification of jadeite is based on its texture, color and volume, and the price is different when it enters the market. Therefore, the earliest appraisers who identified the jade grade were jade collectors and jade merchants (Jia). In addition to jade materials, the identification of jade articles should also include design and production costs, circulation fees, profits, etc., and be priced according to grades.

Jade is used exclusively by the emperor and the court, but it is forbidden by the people. However, in the Song, Yuan, Ming and Qing Dynasties, the ban on jade was relaxed, and jade materials also flowed into the people. According to the archives of the imperial palace in the Qing Dynasty, He Yuti was divided into five grades in the imperial palace, the first and second grades were used by the imperial palace, and the third to fifth grades were stored for later use. Emperor Qianlong (1736- 1799) classified the imperial palace jade, and what he saw seemed to be Grade A, Grade B and Grade C. Before the Qing Dynasty, the classification of jade and jade was based on the experience of appraisers, which can be described as a traditional appraisal method.

In the 20th century, China introduced scientific and technological equipment to detect jade, and analyzed its chemical composition, microstructure and physical properties, which was called scientific identification method. However, the evaluation of jade and jade articles still depends on experience, and scientific inspection methods are rarely used.

The English name of crystal is Rockcrystal, also known as spar and crystal stone.

Crystal is a colorless and transparent timely crystal mineral. Its main chemical composition is silicon dioxide, which is a substance that "comes out of the uterus" with ordinary sand. When the silicon dioxide crystal is perfect, it is a crystal; Silica becomes agate after gelatinization and dehydration; Water-containing silica gel becomes opal after solidification; When the particle size of silica is less than several microns, chalcedony, flint and secondary quartzite are formed.

The crystal with perfect crystallization belongs to hexagonal system, often in hexagonal prism shape. The cylinder is pointed at one end or at both ends, and many long cylinders are connected together, commonly known as the crystal family, which is beautiful and spectacular. The crystal of silicon dioxide is incomplete, and its shape can be described as varied. Go to Hainan Crystal Exhibition Hall, and you will be an eye-opener: in addition to the common long columns, there are sword-shaped, plate-shaped, short columns and double cones. Some are as small as fingers, and some are as big as boulders; Some are less than half a second, and some weigh more than 300 kilograms.

1824, an Austrian mineralogist named Frish Moss extracted 10 varieties from many minerals, and determined their relative hardness through scientific experiments, from which the crystal hardness was Mohs 7. Although the American National Bureau of Standards later used and popularized the more scientific Knoop hardness tester, jewelers in many countries in the world are still used to using Mohs hardness tester.

Well-crystallized crystals usually have a good herringbone fracture with parallel ridges; In amethyst and heat-treated topaz, most of them are uneven sheet fractures.

Crystal specific gravity: 2.56-2.66g/cm3.

This means that the weight of a certain volume of crystals is 2.56-2.66 times that of the same volume of water. Bulk crystals may have a slightly higher density.

Crystal stripes: colorless.

Stripes, commonly known as colors, are the result of human eyes' perception of light with a certain wavelength.

The transparency of a crystal is related to the quality and quantity of light passing through it. The transparency standard is that when light passes through crystal fragments or slices with a thickness greater than 1 cm, the reflected image can be clearly seen. If the bottom image is not clear enough and only the outline is seen, it will be translucent.

Crystal luster: glass luster. This is true for both polished and fractured surfaces.

Gloss refers to the optical characteristics of reflected light on the surface of a gem. Crystal does not reflect beautiful starlight stripes like starlight sapphire and starlight sapphire, nor does it shine with light blue waves like moonstone, nor does it shine with colors like opal.

To observe the luster of the crystal, you can hold it in your hand and look at the surface reflection with the light of a lamp or a window. The brightness of transparent crystal is related to its luster.

Refractive index of crystal: 1.544- 1.553, which is almost within this range.

Refractive index is the ratio of sine of incident angle to sine of refraction angle when light penetrates into gem crystal from air and produces refraction phenomenon.

Crystal refractive index: 0.009 (maximum), very stable.

Optical characteristics of crystal: uniaxial crystal positive light.

Crystal dispersion: 0.0 13.

Dispersion means that the refractive index of a gem changes with the change of illumination light. For example, the refraction of red light by diamonds is 2.405; 2.427 is the green light; Purple light is 2.449.

The melting point of the crystal is 17 13 degrees Celsius. In the experiment, it was found that it was brittle when heated. The crystal is baked in the flame of a flame burner. Unless it is well protected and cooled slowly, the crystal is easily broken. This kind of temperament has been thoroughly understood by the ancients. Introduction to Natural History reminds us: "Anyone who uses crystal objects should not pour hot soup into it, that is, the powder will crack like a broken one."

Another temperament of crystal is that it is afraid of alkali and acid (except hydrofluoric acid), which is determined by the characteristics of silicon oxide.

Gems such as agate often emit a special smell when heated, rubbed, blown or hit, which reminds people of garlic, horse meat, radish, pine and so on. However, the crystal has no peculiar smell in the above case.

Attached:

Chemical composition and properties of crystals;

The chemical formula is silicon dioxide. Pure colorless and transparent crystal is a variety of seasonable. The chemical composition contains 46.7% silicon and 53.3% oxygen. Because it contains different mixtures or mechanical mixtures, it has many colors. Purple and green are caused by iron (Fe2+) ions, purple can also be caused by titanium (Ti4+), and other colors are caused by color centers. The crystals contain sandy and fragmented goethite, hematite, rutile, magnetite, garnet and chlorite. Hair crystals are formed by inclusions containing hairy needle-like minerals visible to the naked eye. Containing manganese and iron is called amethyst; Iron (golden or lemon) is called topaz; Rose color containing manganese and titanium is called rose season; Smoke color is called smoke crystal; Brown is called tea crystal; Black and transparent are called ink crystals; The light green one is called stone pulp.

Crystal structure and morphology:

It belongs to the tripartite crystal system. The crystal is prismatic, with a hexagonal cone, the cylinder has horizontal stripes, and amethyst often has angular stripes. In nature, crystals are often produced in groups with beautiful shapes. .

Physical properties of crystals:

Crystal is colorless, purple, yellow, green and smoky. Glass luster. Transparent to translucent. Hardness 7. Sexually fragile. The specific gravity is 2.65. No cleavage. Shell fractures also have good herringbone fractures with equal ridges. Amethyst has obvious dichroism, while topaz and tea crystal have weak dichroism. Light emitting crystals have strong phosphorescence. Green gold placer crystal emits gray-green fluorescence under long-wave and short-wave ultraviolet irradiation. It has cat's eye, rainbow and placer gold effects. The crystal is piezoelectric.