Corundum is a precious stone from a jeweler's point of view. The chemist will say that this is just aluminum oxide, the color of which is given by inclusions of iron, chromium, vanadium, titanium, etc. Impurities, which are about 2% in percentage terms, replace
aluminum in the crystal lattice of the mineral. Surprisingly, the same atoms / ions in different minerals can behave differently. For example, chromium gives corundum a red color, beryl (related in composition) green, and chrysoberyl green in the morning and red (alexandrite) in the evening. Such a chameleon.
Corundum transparent intensely colored in the jewelry world has its own names. Red minerals are known as rubies, green minerals are known as chlorosapphires, blue minerals are known as sapphires, and colorless minerals are known as leucosapphires. In the old days, purple stones were called Bengal amethysts, purple - violets, red-violet - almandine sapphires. Transparent corundum, an orange-colored stone, was called padparadscha, and yellow-pink - padparadshah.
In the old days, in the names of various variants of this mineral, jewelers and merchants used the word "oriental", which was supposed to emphasize the quality of the stones. Oriental diamonds, Oriental emeralds, Oriental aquamarines,oriental topazes and oriental chrysolites are all corundums of corresponding shades. It is good that these names are not used now, otherwise there would be confusion.
Sometimes there is corundum stone with asterism effect. In such specimens, a regular six- or twelve-ray star is visible, the rays of which, when the stone is turned, move along its surface. Star sapphires and rubies are highly valued.
Corundum is a hard stone (on the Mohs scale - 9). It is surpassed in hardness only by diamond. Due to this property, non-jewelry stones are used as abrasive materials (for cutting and grinding metal, glass). By the way, the word "emery" is a synonym for the word corundum. This mineral is also in demand as a refractory material.
Now the production of artificial corundum has been established. They are obtained by melting bauxite with iron filings (as a reducing agent) in electric furnaces. Most of them are used in technology, only a few stones go into jewelry. For example, synthetic rubies are used in the watch industry as reference stones, leucosapphires are used in the radio-electronic industry.
Corundum is mined mainly in India, Burma, Madagascar, Thailand, Sri Lanka. There are also deposits in Russia (in the Krasnoyarsk Territory, Primorye, Chelyabinsk Region, in the Urals).
Corundum is a stone that has long been recognized by lithotherapists. And they use it depending on the color. It is believed that the blue stonesnormalize eye pressure. Red - improve blood flow, activate the activity of the glands, balance the metabolism. Violet - alleviate various neuralgia and mental disorders. Orange - rejuvenate, improve digestion.
Corundum (stone) as a mascot is great for psychologists, doctors, teachers, as well as all women who have celebrated their 40th birthday.
