morphological character
According to the shape of the bottom, rhinestones can be divided into two categories: sharp bottom drills and flat bottom drills, and according to the shape of the table, they can be divided into ordinary drills and irregular drills. Shapes of irregular diamonds can be divided into diamond (horse's eye stone), trapezoid diamond, satellite stone, drop-shaped diamond, oval diamond, octagonal diamond and other facets: a general diamond has eight facets, and the back of the diamond is plated with a layer of mercury. By concentrating the section, it has good brightness. The more cutting surfaces, the better the brightness. Swarovski was the first person to discover the cut surface of crystal glass.
Shi Ying crystal is a colorless and transparent large-scale timely crystal mineral. Its main chemical composition is silicon dioxide. The chemical formula is silicon dioxide. Crystal is colorless, purple, yellow, green and smoky. Glass luster. Transparent to translucent. Hardness 7. Sexually fragile. No cleavage. Crystal density: 2.56-2.66g/cm3. Refractive index of crystal: 1.544- 1.553, which is almost within this range. Crystal dispersion: 0.0 13. The melting point of the crystal is 17 13℃.
Basic attribute
physicochemical property
1, hardness: Mohs hardness 7, which is equivalent to the hardness of a steel file. 2. cleavage: no. Cleavage refers to the property that minerals crack regularly in a certain direction to form a smooth plane when they are hit. According to cleavage degree, it can be divided into five categories: extreme perfect cleavage, perfect cleavage, moderate cleavage, imperfect cleavage and no cleavage, and crystal belongs to no cleavage. 3. Fracture: Shell-shaped. Fracture is also called fracture. It refers to the irregular fracture of minerals 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. 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. Crystal melting point: the crystal melting point is 17 13℃.
chemical composition
Crystal and ordinary sand are substances that "come out of the womb together". 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. Pure colorless and transparent crystal is a variety of seasonable. The chemical composition contains 46.7% silicon and 53.3% oxygen. It appears in many colors because it contains different mixtures or is mechanically mixed. 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.
Structural morphology
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. 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. When you go to China Crystal City, you will definitely 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 a treasure map-crystals.
Refers to, some as big as boulders; Some are less than half a second, and some weigh more than 300 kilograms. President Mao Zedong's crystal coffin was finally made of high-quality natural Donghai crystal. At present, the largest crystal is also from Donghai County, Lianyungang. 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.
evaluation criterion
The evaluation standard of crystal is different from that of high-end gemstones. Most high-end gemstones put color first when evaluating, but for crystals, color and clarity (called crystal in the crystal industry) are almost equally important factors: 1, color: color is very important for any gemstone, and crystals are 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. 3. Impurities: If there are legendary figures in the impurities inside the crystal, such as Buddha, constellation, zodiac, etc., its value may be higher than that of the crystal with the same color and clarity.
Appearance and morphology
The crystal belongs to hexagonal 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 is 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℃. 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 king of the world.
The world crystal king is produced in Brazil. Material: single crystal Donghai Crystal King (in Donghai Crystal Market)
Specification: Height: 260cm 153cm This crystal weighs 28.6 tons, and it is pure single crystal silicon dioxide, which is hexagonal.