British crystal includes both colorless transparent glass (K9, ordinary glass is blue) and rock crystal ore. Therefore, in order to facilitate the distinction, Rockcrystal is usually referred to as rock crystal for short, also called spar and crystal stone. 1676 Englishman George Ravenscroft discovered the crystal.
Physical and chemical properties of crystals [2]
1. Hardness: Mohs hardness is 7, as hard as a steel file, which dwarfs fragile gems such as topaz, opal and emerald.
2. cleavage: no. Cleavage refers to the property that when minerals are hit, they often crack in a certain direction regularly to form a smooth plane. According to the complete degree of cleavage, it can be divided into five categories: extremely perfect cleavage, perfect cleavage, moderate cleavage, imperfect cleavage and no cleavage, while crystal belongs to no cleavage.
3. Fracture: Shell-shaped. Fracture is also called fracture. It means that minerals only break irregularly after being hit, and the irregular fracture surface is called fracture. According to the fracture shape, it can be divided into shell-shaped and serrated.
4. Specific gravity: The specific gravity of the crystal is 2.56-2.66g/cm3. The weight of crystal with the same volume is 2.56-2.66 times that of water with the same volume, and the density of bulk crystal may be slightly higher. [ 1]
5, streaks: colorless. The color of mineral powder is called stripes. It can eliminate false colors, weaken other colors and keep its own color, which is one of the more reliable identification features than mineral colors.
6. Transparency: transparent and translucent. The transparency of minerals is called transparency. The transparency standard of crystal 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 is translucent.
7, luster: glass luster. Gloss refers to the ability of mineral surface to reflect light. To observe the luster of a crystal, you can hold it in your hand and look at the surface reflection through the light projected by a lamp or window. The brightness of transparent crystal is related to its luster.
8. Refractive index: The refractive index of the crystal is 1.544- 1.553, which hardly exceeds this range. Refractive index refers to the ratio of sine of incident angle to sine of refraction angle when light penetrates into gem crystal from air and produces refraction phenomenon.
9. Melting point of crystal: The melting point of crystal is 17 13 degrees Celsius. [Edit this paragraph] Chemical composition and properties of 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.
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 time, that is, pink crystal; Smoke color is called smoke crystal; Brown is called tea crystal; Black and transparent are called ink crystals. [Edit this paragraph] Physical properties of crystals 1824 Austrian mineralogist Frish Moss extracted 10 varieties from many minerals, and determined their relative hardness through scientific experiments, from which it was concluded that 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.
The crystal with perfect crystallization belongs to the tripartite system, which is often hexagonal prism. One end of the cylinder is pointed or two ends are pointed, and many long columns are connected together, collectively called crystal clusters, which are 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 treasure maps-crystal fingers, and some are as big as boulders; Some are less than half a second, and some weigh more than 300 kilograms.
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.
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.
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. The museum guide reminds: "If you use crystal objects, don't splash them with hot soup, that is, the powder will crack like a broken one."
Evaluation standard of crystal
The evaluation standard of crystal is different from that of high-end gemstones. Most high-end gemstones put color first when evaluating. For crystals, color and clarity (called crystals in the crystal industry) are almost equally important factors:
1, color: For any gem, color is very important, and crystal is no exception. If the crystal is colored, such as pink crystal, topaz, amethyst, etc. The highest standard of color evaluation is bright and moving, and there are no other shades such as gray, black and brown. Such as pink crystal, the color is better with pink; Amethyst, bright purple in color, pure but not black; Topaz, the required color does not contain green and lemon tones, and golden orange is preferred. For hair crystal, the color of crystal is also very important. Golden hair crystal hair, crystal completely colorless (white crystal) slightly brown, the visual experience of the naked eye is also different, so the price of the former will be higher than the latter.
2. Clarity: The clarity requirements of crystals and high-grade gems are quite different. High-grade gems are scarce, so people generally don't ask too much for the purity of high-grade gems. However, the output of crystal is really amazing, so people usually require the higher the purity of crystal, the better, and try to avoid crystals with obvious inclusions. [Edit this paragraph] Appearance and morphology of crystal-topaz
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. . 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 stripe color: colorless.
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. [Edit this paragraph] Crystal production Basically, the most important component of crystal is "silicon dioxide", and "silicon dioxide" is also the most important mineral occupying more than 65% of the crust composition; It also contains various trace metals, so it will cause crystals of different colors; Moreover, crystals are widely associated with various minerals in nature, such as mica, feldspar, calcite, tourmaline, rutile, granite and so on.
The growth environment of crystals is mostly underground and caves, which requires rich underground water sources, and groundwater mostly contains saturated silicon dioxide. At the same time, the pressure in it is about two to three times that of atmospheric pressure, and the temperature is between 550 and 600℃. If given proper time, the crystal will follow the natural law of "hexagonal system"
Usually, in the ideal environment controlled by human beings, that is, when the physical and chemical conditions meet the above conditions, the growth rate of crystals is about 0.8 mm per day. This is also the standard production speed of many intraocular lenses in laboratories and factories. The crystal thus cultivated is the so-called "synthetic Shi Ying", which is usually cut into chips and used in electronics, computer and communication industries. Some people call it "breeding Shi Ying". Although they use different words, they actually mean the same thing. Generally, the thickness of industrial intraocular lens is about 3 cm, that is, 30mm, and it takes about 40 days to grow. It generally takes about180 days for jewelry industry to grind a crystal ball with a size above 10 cm (100mm). However, this speed is only possible in the most ideal environment controlled by human beings. In nature, the situation is not so optimistic because of raw materials, water quality, temperature, pressure and other conditions. Are constantly changing, it is difficult to achieve the ideal situation. It usually takes tens of thousands or millions of times to achieve the same growth. This is the reason why the "geological age" movement takes "million years" as the calculation base, and it is also the precious place of "crystal rock".
When a normal crystal is growing, people often find that the growth line is parallel to the cylindrical tip line. Because of the small growth space in underground and caves, especially in the event of earthquakes or crustal changes, they are even easily squeezed by other minerals, and different "crystal planes" often appear. Also, when crystals are still in liquid state, they are often wrapped by other minerals and marls and grow together, such as rutile (which will become crystals later), volcanic marls (which will become phantom crystals later) and so on. These are "part of nature", please don't treat them as "flaws".
The source of the crystal:
Donghai County, Lianyungang City, Jiangsu Province is rich in crystals and is known as the Crystal Capital.
The crystal stone found in Donghai County, Lianyungang City, Jiangsu Province, weighs 1 1.32 tons and has a ruddy appearance. It is the heaviest crystal stone in Asia. In addition to Jiangsu, Tunchang, Hainan Province is also rich in crystals.
Anfeng Town, Baoying County, Yangzhou City, Jiangsu Province is known as the "No.1 Crystal Town in China", which is rich in all kinds of crystals and crystal handicrafts. Such as the well-known enterprise Shunyuan Crystal Company.
Types and classification of crystals
First, timely (single crystal Shi Ying)
White crystal (white crystal)
Amethyst (amethyst)
Topaz (topaz)
Smoked Shi Ying
Powder Crystal (Hibiscus Rose Shi Ying)
Milky white Shi Ying
Hair Crystal (Rutile Shi Ying)
quartz cat's eye
Red Shi Ying, etc.
2. cryptocryst
The shape of the crystal is so fine that it needs a microscope to see it clearly. The appearance looks smooth and blocky. The most common are all kinds of agates.
Such as peeled agate
Moss agate (moss agate)
Blue lace agate
Agate with water
Chalcedony, etc. [Edit this paragraph] Different uses of crystals ① Focusing and refractive focusing.
In ancient times, people have found that the focusing function of crystal can also refract light, and convex and concave lenses can be made through this characteristic of crystal. Powerful and highly parallel, the cutting-edge can be used for eye surgery, and the giant can be used for [Star Wars Project] to destroy incoming missiles and so on.
② storage data storage
When a message passes through the crystal, it will be recorded by the crystal, and the chip in the computer memory has this function. In modern times, the lens and prism of spectrometer have been manufactured. Piezoelectric crystals have different positive and negative charges, which are between 0 and 1 in computer binary. Yes, this is the basis of computers. Today, this memory storage capacity is amazing, and all the data of Encyclopedia Britannica can be input in a volume smaller than an eraser.
(3) transmit information.
The information transmission in many electrical appliances also depends on the chip, because the frequency of crystal oscillation is stable and the error of transmission mark is very small. Because the oscillation of crystal chip is very accurate and regular, it can be used not only for the time control of electronic watches, but also for the accurate calculation of computers and the transmission of huge information between computers.
④ Energy conversion transformation
Crystals can convert different energies into other energies, such as light energy, heat energy, acoustic energy and magnetic energy, and can also convert these energies into electric energy. The conversion of solar energy into electric energy depends on the heat collecting chip. Energy can be converted, such as solar collector chip, which can convert light into electricity and electricity into magnetism. Sound, light, electricity, heat and magnetism are all energy sources, which can't be extinguished, but are transformed into different States, and crystal is the best matchmaker.
⑤ Energy amplification
Crystals can enhance energy without changing frequency. For example, when a speaker is used, the current is converted into acoustic energy by time (that is, energy conversion), and then the acoustic wave is enhanced (energy expansion), and there will be no sound loss (frequency unchanged). Electronic signals with the same frequency can be amplified at the same frequency. For example, the crystal on the radio receiving surface will receive the electric waves in the air, and then convert them into sound waves that people hear after amplification. And the multiple between the two is more than ten million times.
After introducing the scientific analysis and verification of crystals, let's look at the classification of crystals. There are various classifications of crystals, which can usually be roughly divided into three categories:
① Crystal variety (crystal)
Usually, we watch clusters of crystals generated by multiple hexagonal crystal columns (hexagonal crystal system), which belong to the category of crystal varieties, such as white crystal, amethyst, topaz, powder crystal, hair crystal, tiger eye stone and so on.
② cryptocrystalline varieties (cryptocrystalline varieties)
The appearance of aphanitic crystals is fragments, not hexagonal clusters, but also belongs to hexagonal system. However, we can't observe their hexagonal crystals with naked eyes, because the crystals are very small, and they can only be seen with the help of a microscope. And this is very smooth in the crystal, because there is "hydrated silica" between the crystals, and agate belongs to this category.
③ Special varieties (special categories)
This kind of crystal is very different from ordinary crystal, so it is difficult to classify it as obvious crystal or invisible crystal, so it is classified as a special kind, such as Skelton crystal with strange uneven crystals and phantom crystal with landscape stars.
The difference between crystal stone and artificial crystal-crystal stone is all over the world, mostly produced in South America such as Brazil and Uruguay, and also produced in the Qinghai-Tibet Plateau. They grow underground or deep in caves, and the air pressure needs to be about 2 to 3 times that of the ground. In addition, there must be a steady stream of groundwater containing saturated silicon dioxide, and the temperature needs to be between 500-600℃. After tens of thousands or even tens of millions of years, silicon dioxide will form crystals and wait for people. But now that technology is developed, the demand for crystals is increasing day by day. Therefore, we imitate the real growth environment in the factory, mass-produce crystals and cut them into chips to meet industrial purposes. This is artificial crystal, commonly known as crystal cultivation. The growth rate of crystals produced by the factory is quite amazing, reaching 0.8 mm per day. Generally, the 3cm thick quartz for industrial use can be produced in about 38 days, so its value is far less than that of crystal. Artificial lens has low value and fast growth rate. One should be ground into a crystal ball in time, and it can be produced in less than half a year, while the growth time of other crystal chains is even shorter, but it takes tens of millions of years for rock crystals. Rock crystals have absorbed tens of millions of years of energy from nature, which is absolutely incomparable to artificial crystals. We often bring crystals to change our energy and magnetic field.
Crystal, recycled crystal and craft crystal-
Crystals are formed under natural conditions.
Regenerated crystals are single crystals, also known as synthetic crystals and piezoelectric crystals. Regenerated crystals are made by hydrothermal crystallization "imitating the growth process of rock crystals". Put natural silica ore and some chemicals into an autoclave and gradually cultivate for 1-3 months (for different crystals). The chemical composition, molecular structure, optical properties, mechanical and electrical properties are completely the same as those of rock crystals, while the regenerated crystals are purer and have better color than rock crystals in birefringence and polarization. After processing (cutting, grinding and polishing), particles of various shapes are crystal clear, dazzling, wear-resistant and corrosion-resistant.
Craft crystal, also called imitation crystal, is made of lead glass or rare earth glass, which has no impurities and good transparency. [Edit this paragraph] The difference between crystal and glass If the proportion of lead oxide in glass reaches more than 24% and the refractive index reaches 1.545, it can be called crystal.
A variety of crystal shapes
Rock crystals are hexagonal columns, triangular bipyramid, condenser, conical surface with horizontal stripes, twins with water drops, and their crystal faces are round beads.
Piezoelectric crystals are rod-shaped, with special fish-scale growth lines, no crystals or twisted crystal buds with parallel cylinders at the center of the crystals.
Glass has an irregular shape, and water droplets immediately spread on its surface.
Glossy hardness cleavage fracture of varieties
Crystal stone is clear as water, Mohs 7 has no cleavage, conchoidal fracture, parallel fracture and obvious ridge.
Piezoelectric crystal luster white 6.8-7 Shell fracture is incomplete.
If the glass smokes, the color will be red 5.5-6. The fractures are parallel and the ridges are not parallel.
Characteristic specific gravity of various inclusions
The inferior crystal has irregular inclusions and cotton-wool bubbles. 2.56-2.66
Piezoelectric crystals have regular circular, elliptical or elongated regular debris inclusions and bubbles. About 2.6
Regular bubbles and inclusions are common in glass. 2-2.20 or so, but aluminum glass is relatively heavy.
Hand-feel optical characteristics of varieties
The rock crystal is obviously cooler, and the refractive index is 1.544- 1.533.
Piezoelectric crystal has similar cold light sensitivity to rock crystal, and its extinction speed is slower than that of rock crystal.
The temperature-sensitive refractive index of glass is about 1.40, which is completely extinction. Optical glass cannot transmit light, but there is no extinction phenomenon. [Edit this paragraph] How to distinguish between rock crystals and synthetic crystals Fashion collectors like to collect rock crystals, but they are often deceived by a large number of synthetic crystals on the market. Crystals on the market:
Fused crystal (synthetic crystal): quartz powder, glass slag, crystal waste, etc. are mostly used. The hardness of molten crystals is generally between 5.5 and 6, so its hardness is lower than that of crystals. (Crystal is 7)
Aquaculture crystal: Aquaculture crystal refers to taking stone crystal as seed, and then applying high pressure to the stone crystal to make it grow. There are molecules rich in silica in the incubator. Then silicon dioxide molecules grow around the rock crystal, and the crystal composition (molecular formula) is exactly the same as that of the rock crystal. The only difference is that the magnetic field of this crystal is not as strong as that of rock crystal.
PS: In fact, the so-called austenite is often the lead ratio. Generally speaking, adding lead to glass will make the color and clarity of glass better.
How to distinguish between rock crystals and synthetic crystals?
① At first glance: During the formation of rock crystals, there are always some impurities affected by the environment. When observing the sun, you can see bright, uniform and tiny horizontal stripes or catkins. The fake crystals are mostly made of inferior crystal slag and glass slag, which are melted, polished and colored, without 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 make you feel cold and cool. Fake crystals are not cool.
③ Illumination: The crystal can emit beautiful light from any angle when placed vertically in the sun. Fake crystals don't work.
4 Hardness: The hardness of the crystal is high, so it will be lightly scratched on the jewelry with gravel, leaving no trace; If there are stripes, it is a fake crystal.
⑤ Inspection with a polarizer: When rotated 360 degrees under a polarizer, the rock crystal with four bright and four dark changes, and the pseudocrystal without change.
⑥ Check with dichroism: natural amethyst has dichroism, while fake amethyst has no dichroism.
⑦ Examination with a magnifying glass: When examined with a magnifying glass of ten times under the transmitted light, the bubbles that can be found can basically be 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. This crystal is a rock crystal, mainly because it has birefringence.
⑨ Detection with thermal conductivity meter: Adjust the thermal conductivity meter to green 4 squares to detect gems, and the rock crystal can rise to yellow 2 squares, while the false crystal does not rise, and when the area is large, it will rise to yellow 1 square.
Artificial crystals are divided into molten crystals and cultured crystals:
According to Wang Yi, a crystal expert, as the value of crystal increases, more and more people like it, and crystal also attracts the interest of counterfeiters. At this stage, the common methods of counterfeiting in China crystal market are as follows:
Pictographic crystals: Some crystals have vivid scenery. Don't patronize the pictographic scenery in the crystal. Now many people have been able to apply AB glue to the extreme, cut the crystal, add a landscape (mostly small trees and animals) in the middle, and then stick it together. When I held it in my hand, it was beautiful. When I bought it, I thought it was very valuable for investment and collection. Unfortunately, this is artificial.
Titanium crystal tree: Titanium crystal is the most expensive crystal, and counterfeiters will certainly not let go of such a good product. It is entirely possible to grow tree-like titanium crystals in natural environment, but there are few such products. How did our counterfeiters do it? Make a hole under the white crystal and spot it into a plate-shaped titanium crystal with a laser, so that the value of this crystal can soar dozens of times. Usually, some titanium crystal torus will be formed by cutting titanium crystal parts into plates and bonding them with round crystals.