Stone corundum and its properties

Many have a rumor of the names of such famous and luxurious gems as ruby ​​and sapphire, which are harder to give in only to diamond, but few know that both gems have one common name - corundum.

Description of mineral
Description of mineral
  • Kinds of corundum
  • Chemical composition and physical properties of stone
  • History of stone
  • Corundum deposits
  • Mineral healing properties
  • Magical properties of corundum
  • Corundum and zodiac signs
  • Application of gem
  • How to distinguish natural corundum from counterfeit
  • Interesting facts about stone
  • Stone care
  • Pictures of stone corundum and its products
  • Description of the mineral

    Corundum is a group of minerals combined by identicaltrukturoy, chemical composition and physical properties. For a long time, each of the representatives of this group of minerals was considered an independent stone, and only a couple of centuries ago, thanks to the development of such sciences as chemistry and geology, the truth was established.

    The name corundum presumably occurred either from the Sanskrit words "kauruntaka" or "kuruvinda"( which means "ruby") or from the Tamil word "kurundam" - in ancient times this stone was called in India and Ceylon.

    Other well-known world names for corundum are oriental diamond, almandine sapphire, violet, padparadzha, padparadshah, chlorosapphire, leucosapphire, etc.

    Pure corundum is absolutely transparent and colorless with a bright glass shine stone. Such corundums are highly valued in the world market, becauseare rare in nature. Often find crystals of corundums with colloidal and other inclusions that color the mineral in different colors - juicy-scarlet, cornflower blue, yellow, purple, bluish and green.

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    Corundum varieties

    Among the most valuable and known varieties of corundum, the championship is undoubtedly occupied by such precious stones as sapphire and ruby.

    1. Ruby is a transparent corundum of red hues. Its color range ranges from pale-red to a saturated dark-cherry. The most valuable in this variety of corundums are stones of juicy dark red and bright crimson. This is one of the most famous and expensive stones in the world.
      Kinds of rubies:
      • Siamese rubies - corundums of brownish-red and violet shades.
      • Ceylon rubies - corundums of lilac and violet-red colors.
      • Starry rubies - rare exotic gemstones with the original asterism effect - an optical effect, in which a star shape can be seen on a crystal cut. Usually such corundum is processed in the form of cabochons.
    2. Sapphire is a transparent corundum of blue hues. Not less valuable than ruby. It also refers to the precious stones of the first category. Its color range varies from pale blue to a saturated bright cornflower blue color. The most valuable in this variety of corundum are stones of medium color saturation of deep shades. However, in nature there are sapphires and other color schemes: yellow, pink, orange, purple. These are the so-called "fantasy sapphires".
      Species of fancy sapphires:
      • Leucosapphires are absolutely transparent corundums, also called "Oriental sapphires".In ancient times, this jeweler's stone was called "Oriental diamond".
      • Padparadzha - corundums of yellow-orange, pinkish or saturated orange. In translation from Indian, the name of this variety of sapphire translates as "lotus flower".Clean saturated large samples of padparage are valued on a par with diamonds.
      • Chlorsapphire is one of the most valuable species among fantasy sapphires. Its color scheme is green. Due to its external similarity to the emerald, chlorosapphire in ancient times was called the "eastern emerald".
      • Purple sapphire is a corundum of a saturated purple color. In ancient times, this jeweler's stone was called the "eastern amethyst".
      • Star Sapphire is a beautiful rare jewel with an exotic asterism effect. Like the starry ruby, the starry sapphire is also processed in the form of cabochons.

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    Chemical composition and physical properties of the stone

    In its chemical composition, corundum is alumina( alumina).For its formation in natural conditions, a deficiency of silica and a high content of alumina is necessary.

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    This mineral contains 53.2% aluminum( Al).Its chemical formula is Al2O3.

    In its pure form, corundum is a very hard, coarse or fine-grained transparent or translucent stone of grayish color, less often - absolutely colorless with glass shine.

    It often contains various admixtures: chromium( Cr), iron( Fe), manganese( Mn), titanium( Ti), which color corundum in various shades and form a variety of minerals.

    Thanks to chromium impurities, which color corundum in red shades, rubies are formed, and due to the presence of titanium, which colors corundum in blue tones, sapphires are formed. Iron gives corundum brown shades, and in combination with manganese - pink. Yellow shades of corundum are due to the presence of iron oxides in them.

    When heated, corundums lose their color saturation: stones of pale violet and yellow shades fade and may lose their coloring at all, and stones of rich purple shades become pink. But x-ray irradiation, on the contrary, stains even colorless stones, and shades of colored make it even more intense and intense.

    All representatives of this group of minerals are uniaxial, have a correct crystalline structure and possess birefringence, i.e.the property of splitting a beam of light into two rays.

    On the Mohs scale, the hardness of corundum is 9( it is higher only for diamond), and its density varies from 3.94 g / cm3 to 4.10 g / cm3.In sapphires and rubies, the density is a constant value of 4.00 g / cm3.

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    History of stone

    Corundum is known to mankind for more than one century. Also the chief priests of Judea and the priests of Ancient Egypt wore decorations with corundums( sapphires).

    In Europe, the stones of this group of minerals were brought from India. This is also the cause of the name of the stone: "eastern emerald", "eastern amethyst", "eastern diamond".Here corundum quickly became very popular and demanded stone, including - in the form of diplomatic gifts. Presented as a gift, blue( sapphire) or red( ruby) corundum was considered a manifestation of a good tone in the light of higher diplomacy.

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    In Russia, corundums have been known since the Middle Ages, though, then they were called "yakhontami."For example, the ruby ​​was called "chervlennym yahontom", and sapphire - "azure".

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    Corundum deposits

    The most famous large corundum deposits are in India, Burma, USA, Canada, Africa( in the Malagasy Republic, Zimbabwe and South Africa), on. Sri Lanka, Thailand, Norway, Kazakhstan, Madagascar, Greece, Turkey and Russia( in the Urals, Primorye and the Krasnoyarsk Territory).

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    The healing properties of mineral

    According to most lithotherapists, the therapeutic properties of corundums directly depend on their color.

    1. Blue corundums are useful for:
      • treatment of eye diseases;
      • normalization of elevated ocular pressure.
    2. Red corundums promote:
      • improve blood circulation;
      • activation of the activity of endocrine glands;
      • normalization of metabolism.
    3. Purple corundum can alleviate:
      • mental illness;
      • of various kinds of neuralgia;
      • condition after concussion;
      • depression.
    4. Orange corundum promotes:
      • rejuvenating effect;
      • improved digestion.

    Traditional healers claim that all corundums, without exception, have a beneficial effect on the human body and its individual organs.

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    Magical properties of corundum

    The most important magical property that corundum possesses is its ability to activate all the internal forces of a person and direct them to achieve the set goals and high results. It is believed that he helps people active, purposeful and active, and does not like the lazy and inert.

    It is also considered corundum as an assistant to all who are engaged in intellectual work, including schoolchildren and students. This stone strengthens the craving for knowledge, improves memory, develops mental and analytical abilities.

    However, the effect of corundum on a person depends on many factors: both on its shade, and on the place in which it is worn.

    So, pendants and other jewelry with corundum, which are worn around the neck, can help:

    • heal from unjustified fears;
    • get rid of anxiety;
    • get rid of frequent outbursts of anger and irritability;
    • become more workable.

    Earrings with corundum can help a person:

    • think about the meaning of life;
    • will analyze its actions;
    • will be able to create a harmonious relationship with the world around it.

    A ring or a ring with corundum can help its owner:

    • develop spiritually;
    • reveal hidden talents;
    • realize the ability.

    That's just wearing such a ring to achieve the above is necessary on the middle finger of the right hand.

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    Corundum and zodiac signs

    Astrologers wear allotments with corundums to all signs of the zodiac, except Capricorn and Aries. Moreover, Aries are not recommended decorations with corundums until they reach the age of forty. And the best way corundums affect people born under the signs of Cancer, Aquarius and Pisces.

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    Application of gem

    Different varieties of corundums use:

    1. As an expensive jewelry material. For this purpose, rubies, sapphires and leucosapphires have long been used. Of these, make beautiful inserts in rings, rings, bracelets, pendants, pendants, earrings, brooches and other jewelry.
    2. In the abrasive industry. Of opaque granular corundums, grinding and polishing powders are made, emery, abrasives for grinding wheels.
    3. In medicine( especially in ophthalmology) leukosapphires are used.
    4. In the electronics industry.
    5. As a heat-insulating material.
    6. As a high-grade and high-strength substitute for conventional glass. The so-called "sapphire glass" is used in the manufacture of cameras, mobile phones and even portholes for spacecraft and aircraft.

    However, for technical purposes, today mainly use artificial corundum. Quite often they are found in jewelry.

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    How to distinguish natural corundum from forgery

    To distinguish natural corundums from artificially grown is quite difficult. According to their physical properties, artificial stones are not inferior to natural ones, and in terms of purity and color saturation they sometimes surpass their natural counterpart.

    But if you want to buy exactly the natural corundum, pay attention to:

    1. Price. The cost of artificial corundum is much lower than natural.
    2. The presence of defects. Most natural precious corundums, in particular rubies, often have internal defects.
    3. Presence of natural inclusions. In natural corundums, you can see the presence of impurities, and the presence of gas bubbles.
    4. Color change due to ultraviolet light. Due to the use of artificial sapphires in titanium under the influence of ultraviolet, it will have a greenish tinge.
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    Interesting facts about the stone

    1. The whole millimeter layer of the heat insulator using corundum replaces the five centimeter layer of ordinary mineral wool.
    2. The most famous samples of corundum are in the collection of JP Morgan, stored in New York, in the American Museum of Natural History. Among them:
      • Ceylon sapphire weighing 163 carats;
      • a starred ruby ​​from Burma called "Edith Haggin de Long" weighing 100 carats;
      • is a star sapphire called the "Star of India" weighing 563 carats;
      • a starry purple sapphire called "Midnight Star" weighing 116 carats;
      • Thai purple corundum weighing 34 carats.
    3. The largest ever found corundum is a sapphire weighing 951 carats, which belonged to the King of Burma in 1827.
    4. The collection in Jardin des Plantes, stored in Paris, contains an untreated brown sapphire called "Rospoli" weighing 135 carats.
    5. The Diamond Fund in Moscow holds a beautiful oval sapphire cornflower-colored carcass weighing 250 carats, which refers to the old Russian regalia.
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    Stone care

    Given the hardness of corundum, it is difficult to damage it, it is necessary only to periodically check the stability of the stone in the frame, so as not to spoil the cutting of the stone.

    Clean the corundum in several ways:

    1. Keep in a warmed aqueous solution of baking soda( 120 g), table salt( 30 g) and bleach( 50 grams), prepared based on 0.5 liters of water. Then rinse and dry the stone.
    2. Rinse the stone in an aqueous solution of ammonia( 5-10 drops per glass of water).
    3. Keep in a warm aqueous detergent solution. Then rinse and dry the stone.
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    Pictures of the stone of corundum and its products

    • Jun 09, 2018
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