1. Diamond (Diamond)
Ingredients: Carbon. Hardness: 10. Specific gravity: 3.52. Refractive index: 2.42.
Diamonds are the hardest and lustrous ore on the planet. Clean and colorless diamonds are the most popular, but other variants range from yellow, brown to green, blue, pink, red, black and grey. Since the carbon atoms that make up the diamond are evenly arranged, the crystals are extremely perfect.
Origin: South Africa, Australia, Ghana, Lion Rock, Say, Botswana, Namibia, the Soviet Union, Brazil, the United States.
2. Ruby corundum (Ruby)
Composition: Alumina. Hardness: 9. Specific gravity: 4.00. Refractive index: 1.76-1.77. Birefringence: 0.008.
Available in a variety of red colors, from pink to purple to maroon, depending on the chromium and iron content. Since crystals often appear as twins, they are prone to cracks, but they are actually very tough and the hardness is second only to diamonds.
Origin: The best is produced in Myanmar; in addition, Thailand, Afghanistan, Pakistan, Vietnam, India, Colorado, Russia, Australia, Norway and other places also produce rubies.
3. Sapphire corundum (Sapphire)
Composition: Alumina. Hardness: 9. Specific gravity: 4.00. Refractive index: 1.76-1.77. Birefringence: 0.008.
All non-red corundum with gemstone characteristics are called sapphire. Due to the color changes made by iron and titanium, a variety of shades are exhibited, but the most precious is the clear dark blue.
Origin: Myanmar, Sri Lanka, India, Kashmir, Thailand, Australia, Nigeria, Montana, Khmer, Brazil, Kenya, Malawi, Colombia.
4. Emerald-Beryl
Composition: barium strontium silicate. Hardness: 7.5. Specific gravity: 2.71. Refractive index: 1.57-1.58. Birefringence: 0.006.
Green is derived from chromium and vanadium. It is rare that there is no flaw at all, so the above-mentioned oil color method often compensates for the crack and makes it color. In order to reduce the loss, a stepwise grinding method, that is, a group green cutting method is often used.
Origin: Colombia, Austria, India, Australia, Brazil, South Africa, Egypt, United States, Norway, Pakistan and Zimbabwe.
5. Nephrite Jade
Ingredients: Calcium magnesium citrate. Hardness: 6.5. Specific gravity: 2.96. Refractive index: 1.61-1.63. Birefringence: 0.027.
Nephrite is confirmed to be another jade, which is a fibrous amphibole crystal aggregate. The interlocking structure of steel is considered to be the finest engraving material, originally used as a weapon and later used as a jewelry. The color varies from iron-rich dark green nephrite to magnesium-rich creamy color, which may be homogenous, speckled or striped.
Origin: The history of Chinese engraving nephrite has been more than 2,000 years. The materials were imported from Central Asia and then imported from Myanmar. Others include Siberia (dark green with black spots), Russia (Bocais) and China. Nephrite is also distributed in various rocks in the North Island and South Island of New Zealand. There are also Australia (black nephrite), the United States, Canada, Mexico, Brazil, Taiwan, Zimbabwe (dark green), Italy, Poland, Germany and Switzerland.
6. Jadeite
Composition: sodium citrate aluminum. Hardness: 7. Specific gravity: 3.33. Refractive index: 1.66-1.68. Birefringence: 0.012.
There are two kinds of jade; jadeite (also known as jadeite) and nephrite. Nephrite is more common, but both are tough, fine-grained rocks suitable for engraving. Jadeite is composed of pyroxene crystals with interlocking particle structure, which is available in a variety of colors, including green, light purple, white, pink, brown, red, blue, black, orange and yellow. The most precious emperor jade, represented by the presence of chrome, is rich in dark green. After polishing jadeite, it usually has a dimple-like appearance.
Origin: Jadeite is produced in metamorphic rocks and is produced as alluvial pebbles and boulders. The brown surface is formed by weathering and is often incorporated into the engraving and finished products. The most important source of jade is in Myanmar, which has been providing carving materials to Central American Indians for more than 200 years. Rijiang and California in the United States also have jadeite.
7. Gold Emerald (Chrysoberyl)
Composition: yttrium aluminum oxide. Hardness: 8.5. Specific gravity: 3.71. Refractive index: 1.74-1.75. Birefringence: 0.009.
The colors range from green, greenish yellow, yellow to brown. The texture is hard and durable, making it especially suitable for making precious stones. After careful cutting, it is bright but not fire-colored. The two variants of the stone and the cat's eye gem have their own unique properties. Precious and rare marbles can change from green to red, purple, or brown under incandescence in daylight. Synthetic gold emeralds, corundum and spinel can mimic the color change of the stone. When the opal is smashed into a convex gemstone, white lines pass through the yellow-gray gemstone due to the groove or feathery fluid inclusions, or the rutile needle-like inclusions. The most precious pale golden brown with shadows of the "milk and honey" effect. The pale yellow gold emerald that was loved by the Portuguese in the 18th and 19th centuries was called the olivine.
Origin: The finest gold emeralds include the stone. In the Urals of Russia, most of them have been mined. The largest faceted gemstone here weighs 66 carats. Water-clear pebble of various colors is found in the gemstones of Sri Lanka. It is also distributed in Myanmar, Brazil, Zimbabwe, Tanzania and Madagascar. Opal is produced in Sri Lanka, Brazil and China.
8. Topaz is also known as Topaz.
Ingredients: fluoroaluminum hydroxy citrate. Hardness: 8. Specific gravity: 3.54. Refractive index: 1.62-1.63. Birefringence: 0.010.
Available in a variety of colors: deep golden yellow topaz (sometimes called sherry topaz) and pink topaz are the most expensive, blue and green topaz are also popular. Natural pink topaz is rare, and most of it is yellow jade processed by heat treatment. Many colorless yellows produce different blue colors after irradiation and heat treatment, and some are almost indistinguishable from aquamarine by the naked eye. Some topaz has tear-like holes containing bubbles or several immiscible liquids, as well as other inclusions such as cracks, textures and crepe. Jinghuangyu has a unique rhomboid cross section and stripes parallel to its length, and the cleavage is complete.
Origin: Produced in pegmatite, granite and volcanic lava, also found in alluvial deposits. Produced in Brazil, the United States, Sri Lanka, Myanmar, the former Soviet Union, Australia, Tasmania, Pakistan, Mexico, Japan and Africa. Brazil, Pakistan and Russia are the origin of pink topaz.
9. Opal (Opal)
Ingredients: Hydrated cerium oxide gel. Hardness: 6. Specific gravity: 2.10. Refractive index: 1.37-1.47.
The most hardened cerium oxide gel containing 5-10% moisture. Unlike most gemstones, it is amorphous and will dry out and crack. There are two variants: expensive opal, which will show color flash (iris) due to different viewing angles; ordinary opal, which is opaque and has no iridescence. The opal of the precious opal is caused by the regular arrangement of its structure - a very small ceria sphere - diffracted light: the larger the sphere, the wider the range of colors. Your opal has several different colors.
Origin: filling holes in ore deposits or ore in igneous rocks, forming stalagmites or stalactites, and replacing organic matter in fossil wood, animal hard shells and callus. Australia has been a major producer of opals since the 19th century. Others include the Czech Republic, the United States, Brazil, Mexico and South Africa.
10. Red Tourmaline (Rubelite-Tourmaline)
Composition: composite bismuth borate. Hardness: 7.5. Specific gravity: 3.06. Refractive index: 1.62-1.64 Birefringence: 0.018.
Members of the Tourmaline family have the same basic crystal structure, but the colors are different, the most precious of which is the ruby ​​red tourmaline. The crystal has stripes and has a rounded cross-section and a rounded outline; it may also have a fiber habit that exhibits a cat's eye when cut into a convex shape.
Origin: Russia's pink and red tourmaline is produced in weathered granite, with Madagascar, the United States, Brazil, Myanmar and eastern Africa.
11. é›é’电石
Composition: composite bismuth borate. Hardness: 7.5. Specific gravity: 3.06. Refractive index: 1.62-1.64. Birefringence: 0.018.
The dark blue tourmaline is called indigo tourmaline, which is lightened by heat treatment to make an eye-catching gem.
Origin: Produced in yellow clay of Russian Siberian weathered granite. Bright blue tourmaline is also found in Brazil, as well as Madagascar and the United States.
12. Watermelon Tourmaline
Ingredients: composite bismuth borate. Hardness: 7.5. Specific gravity: 3.06. Refractive index: 1.62-1.64. Birefringence: 0.018.
The tourmaline with pink, green edges or vice versa is called watermelon calcium carbide because the color is like the pulp and peel of watermelon. Many other tourmaline are composed of two or more colors, some containing up to 15 stone-like colors or shades.
Origin: Watermelon tourmaline is distributed in South Africa, Eastern Africa, Brazil and other places.
13. Pearl (Pearl)
Ingredients: calcium carbonate, chitin and water. Hardness: 3. Specific gravity: 2.71. Refractive index: 1.53-1.68.
Produced in shells - especially oysters and mussels - is a natural defense against stimuli such as gravel. The vermiculite layer called the mother-of-pearl is secreted around the irritant and gradually grows larger, forming a strong pearl. The light reflected from these overlapping nacres produces an iridescent sheen, also known as "pearl." In cultured pearls, irritants are often implanted to form pearls. In the "nucleated" cultured pearls, a small bead is used as the core, and the layer of mother-of-pearl is secreted on it. Pearls vary in color, white, slightly white (usually pink) brown or black, depending on the type of mollusks and water. Pearls are sensitive to acid, dryness and moisture, and are not as long-lasting as their treasures.
Origin: For thousands of years, natural pearls have been produced in the Persian Gulf, Manna Bay (Indian Ocean) and the Red Sea. The coast of Polynesia and Australia mainly produces pearls. China and Japan have cultivated freshwater and marine cultured pearls. The freshwater pearls are also distributed in Scotland, Ireland, France, Austria, Germany and the Mississippi River in the United States.
14. Tanzanite
Ingredients: calcium hydroxy citrate aluminum. Hardness: 6.5. Specific gravity: 3.35. Refractive index: 1.69-1.70. Birefringence: 0.010.
There are many varieties, the most popular is Danquan Stone, a variant of sapphire color due to the presence of vanadium. Danquan stone has a remarkable multi-color, purple, blue or stone gray, depending on the viewing angle; it will produce a slight color change under incandescent light. A vermiculite green variant containing ruby, sometimes containing black à amphibole inclusions, polished, engraved or framed to create a decorative or striking decorative gemstone. Manganese meteorite, a pink block-like variant produced by manganese, which can be polished or engraved to make small ornaments. Danquan stone is often confused with sapphire and manganese meteorite. A slight heat treatment of the vermiculite variant can add color.
Origin: First discovered in Tanzania, yellow and green vermiculite are distributed in Tanzania and Kenya, and manganese meteorites are distributed in Norway, Austria, Western Australia, Italy and Carolina.
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