Corundum- mineral, crystalline α-aluminum oxide (Al 2 O 3) (crystalline alumina). The name is of ancient Indian origin (probably from the Sanskrit “kauruntaka” or the Tamil “kurundam” - this is how this mineral was called in India and Ceylon; possibly from the Sanskrit “kuruvinda” - ruby). The corundum stone is well known to mineralogists, chemists, mechanical engineers, electronics engineers - in a word, to everyone except jewelers. And all because corundum is a stone whose properties for the most part have nothing to do with jewelry.
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STRUCTURE
Crystallizes in trigonal system, ditrigonal-scalenohedral type of symmetry. The following polymorphic modifications are known for Al 2 O 3: 1) α-Al 2 O 3 (corundum) - trigonal, the most stable under natural conditions; is formed in a wide temperature range (500-1500°C); 2) β-Al 2 O 3 hexagonal, stable at very high temperatures; the transformation of α-Al 2 O 3 into β-Al 2 O 3 occurs at temperatures of 1500-1800 ° C; this modification is formed during very slow cooling of the Al 2 O 3 melt; 3) γ-Al 2 O 3 - cubic, with a spinel-type crystal structure (same as in the case of maghemite); obtained artificially by calcining aluminum oxide hydrate (boehmite) to temperatures below 950°C; at higher temperatures it is unstable - it turns into α-Al 2 O 3. The crystal structure of Al 2 O 3 is depicted in the form of Al 2 O 3 groups at the corners of two rhombohedrons that make up the unit cell. Despite its apparent complexity, the structure of corundum has a fairly simple structural diagram. Oxygen ions are in a dense hexagonal packing and are arranged in layers perpendicular to the triple axis, superimposed on one another. A1 cations are located between two such layers in the form of a hexagonal network, filling two-thirds of the octahedral voids (i.e., the voids between six oxygen anions, three of which belong to one, and the other three, rotated relative to the first by 180°, to another layer of oxygen ions ). In this case, the groups of every three oxygen ions form a common face for two adjacent octahedra in adjacent layers. It is characteristic that the cationic layers are superimposed on each other in such a way that in each vertical column of octahedra, as well as in the layer, two occupied ones alternate with one unoccupied one, and pairs of occupied octahedra form vertical helical triple axes.
PROPERTIES
The cleavage is imaginary, apparent, due to the strongly pronounced separation caused by polysynthetic twinning. Mohs hardness 9. Density 3.9 - 4 g/cm³. Specific heat of fusion 109.2 kJ/mol
Melting point - 2050 °C. Color varies widely from colorless and gray to various shades of red, blue or purple. Dichroic. Sometimes iridescence is observed on chips along the cleavage.
The luster is strong metallic, to matte. In some cases, due to the regularly located inclusions of the finest rutile needles, oriented along its main crystallographic directions, the effect of asterism is observed. In these cases, they talk about “star-shaped” corundums (rubies, sapphires). Chemically stable, insoluble in acids.
MORPHOLOGY
It occurs in the form of barrel-shaped, dipyramidal and tabular pseudohexagonal crystals, separately disseminated grains and granular aggregates. The faces of prisms, dipyramids and pinacoids are often covered with rough oblique shading. Typically, fairly well-formed barrel-shaped, columnar, pyramidal and lamellar crystals are observed, sometimes reaching large sizes (up to a decimeter in diameter). The most common faces are hexagonal prism (1120), hexagonal bipyramids (2241), (2243), rhombohedron (1011) and pinacoid (0001). Often the faces of prisms and dipyramids, as well as the faces of the pinacoid, are covered with oblique hatching, and in other cases, hatching is observed in the horizontal direction due to twinning along the pinacoid. Corundum as a mineral species has the following varieties:
- Ruby, “red yacht” - red; - a gemstone of the first category; the price of transparent, well-colored specimens can be higher than that of diamonds.
- Sapphire, “blue yacht” - blue of varying intensity. With a moderately intense cornflower blue color, it is a first category gemstone, but is valued significantly lower than a ruby. Sapphires that are too dark or too light are quite cheap. The relationship between sapphire and ruby was discovered in Europe only in 1800.
- Star ruby is an exotic gemstone with an asterism effect, processed as a cabochon - not for everyone.
- Star sapphire is an exotic gemstone with an asterism effect, processed as a cabochon - not for everyone.
- Leucosapphire or “Oriental Diamond” is colorless and completely transparent corundum; inexpensive gemstone.
- “Eastern emerald” - green;
- "Eastern Amethyst" - purple;
- Common corundum is opaque, coarse- or fine-grained, grayish in color. Sometimes in large opaque crystals. Due to its high hardness, it is used as an abrasive material; due to its high melting point, it is used as a refractory material.
ORIGIN
A typical hypogene mineral. It is found in igneous rocks poor in silica (such as syenites, nepheline syenites). Large crystals are found in pegmatites, genetically related to these rocks. Grains and metacrystals reaching up to 10 cm in diameter are characteristic of metamorphic rocks of the deep stage of metamorphism - gneisses, garnet amphibolites, granulites. Also formed during contact-metamorphic changes in sedimentary rocks rich in alumina - emery. The bulk of precious varieties are found in placers.
Related Minerals
Feldspars, andalusite, sillimanite, rutile, kyanite, gibbsite, boehmite, spinel, serpentine, nepheline, chlorites, micas, magnetite.
It cannot coexist with quartz, since the minerals react to form one of the polymorphs of aluminum silicate (kyanite, andalusite, sillimanite).
APPLICATION
The high hardness of corundum determines its practical importance: corundum powder is used for grinding precious stones, metals, and optical glasses. Grinding machine wheels are made from cemented ground corundum rocks. In addition, when glued to paper or canvas, it produces sandpaper. Ruby and sapphire are precious stones. Rubies play the role of bearings and support stones in watch movements, ensuring high precision and prolonging their life. Rubies and sapphires are used in optical quantum generators (lasers). Sapphire does not react with any acids or alkalis. It resists high pressures and temperatures, hard radioactive radiation. It can be welded with glass and soldered to metal (portholes, which allow you to monitor the process taking place in instruments and apparatus where vacuum, high temperatures and pressures reign, bathyscaphe, etc.). For this purpose, transparent, colorless, artificial sapphire is used. Sapphire as a differential pressure sensor is used to detect emergency sections of main gas pipelines.
Corundum (eng. Corundum) - Al 2 O 3
CLASSIFICATION
| Strunz (8th edition) | 4/C.04-10 |
| Nickel-Strunz (10th edition) | 4.CB.05 |
| Dana (7th edition) | 4.3.1.1 |
| Dana (8th edition) | 4.3.1.1 |
| Hey's CIM Ref. | 7.6.1 |
What corundum is is practically unknown to most ordinary people. This term is more often used by professional jewelers. It is general in nature, since it implies a whole group of gems, and not a separate mineral. You might be surprised, but ruby and sapphire have a lot in common. Both stones are corundum. From this article you will learn about what crystals are and what distinctive features this group of gems has.
First finds
Humanity has known about this crystal for more than a millennium. Its beauty was sung in Ancient Egypt and Jerusalem. It was from there that it was later brought to India. Since then, corundum has gained immense popularity in the jewelry world. Scientists hypothesize that the ancients called ruby that way, which was its second name.
The first descriptions of corundum were given by Pliny several thousand years ago. In his works, he described in detail the extraction process and the characteristics of the mineral.
History shows that stone was practically not mined in the Old World in the Middle Ages. Crystal mining has long been practiced in Asian countries, mainly India and Thailand. It is found in places of volcanic eruptions, as well as where sedimentary rocks are located.
Chemical and physical properties
The formula of corundum is Al 2 O 3. This chemical compound is part of clay. Therefore, experts classify the mineral as alumina. Some elements of the crystal lattices of stones vary. This distinctive feature distinguishes the varieties of crystal.
The mineral has good cleavage and hardness (9 out of 10). After splitting, the surface of the crystal is smooth and even. Corundum is processed using diamond. The stone goes from solid to liquid at a temperature of 2050 degrees Celsius.
The color palette of gems is wide. Transparent and multi-colored crystals are found in nature. Untreated products have a matte glass luster.
After jewelry cutting and polishing, the jewelry acquires a unique radiance with a light star effect. This quality is inherent only in precious stones, including ruby and sapphire.
Varieties of many-sided crystal
There are many varieties of corundum found in nature.
Rubies - this group of minerals belongs to precious stones. The color range varies from soft pink tones to dark cherry shades. The richer and darker the red color of the crystal, the higher its value in the jewelry industry.
Sapphires are precious stones whose color scheme is dominated by blue tones. There are light crystals with a slight heavenly blue, as well as rich azure minerals. The rarest specimens have yellow, pink and orange shades. Because of their unusual appearance they are called fantasy.
The cost is not inferior to its relative ruby. And remember an important point: sapphire is corundum, but any corundum cannot be called sapphire or ruby.
Chlorosapphire is corundum, which is compared to emerald for its color and appearance. They call it oriental, like leucosapphire, which resembles diamond because it has a degree of transparency close to it. However it costs much less
Other types of corundum include: purple oriental amethyst, white corundum, yellow and orange padparadscha, and mint oriental gem. Gray corundum, as well as a brown-colored mineral, is considered one of the cheapest. The gray-black granular rock is called emery.
Creations of nature and human hands
Corundums are minerals that are currently grown in laboratory conditions. For this, iron filings and a mixture of bauxite are used, which are fired. The appropriate color is given to the final product through the inclusion of various chemical components.
Ready-made artificial corundum is not inferior to natural corundum in properties and aesthetics. Sometimes such a stone looks more impressive than natural minerals, but its cost is an order of magnitude lower.
Man-made sapphire or ruby are affordable, which makes it possible for even a budget buyer to become the owner of a beautiful piece of jewelry.
Mining locations
The chemical composition of corundum suggests that the elements it contains are common in nature. Therefore, minerals are mined everywhere on the planet. Regions rich in this rock include Turkey, the United States, India, Africa, Thailand, Scandinavia, and Sri Lanka.
In our latitudes, this stone is mined in the Urals (Cherry Mountains), Karelia and in the Krasnoyarsk Territory (Sigangoy deposit). In these regions, those corundums that are of jewelry value are found. Other types (production) are also found in other parts of the Earth - Canada, Norway, the Kola Peninsula.
Use and application
The properties of the mineral are widely used not only for making jewelry. Corundums are used in the chemical, watch and construction industries
In particular, it is used to strengthen the structure of glass. Sapphire crystals are installed in modern gadgets and watches. They are not subject to cuts and scratches, so they retain their presentation for longer.
Stone for technical purposes is also sold in construction stores. This rock is used as a basis for the production of sandpaper or insulating building materials. Corundum is also an integral part of a quantum generator.
As for the jewelry industry, rhinestones are made from budget items. Such crystals are highly durable and therefore resistant to scratches and cuts.
Cost and price range
Since there are several types of stone, the price of a carat depends on whether it belongs to one of them. Crystals with a transparent structure without inclusions are valued higher. Artificial specimens shine more, but their cost is lower. Therefore, when evaluating a gem, it is the level of transparency that is taken into account. The color scheme also matters.
Red and pink rubies are more expensive than all corundums. Sapphires are in second place. Orange padparadscha rounds out the top three most expensive varieties.
Gray and brown stones are not an acquired taste for jewelry, however, it is known that such corundums are also in demand. As for technical breeds, their cost on average is up to 20 thousand rubles per 1000 kg.
Selection of jewelry by stars
The natural mineral emits vibrations that affect the human body, as well as its psycho-emotional sphere. Depending on what zodiac sign a person came into this life under, corundum will have a positive or negative effect on him.
Capricorn and Aries males are people for whom wearing a stone is contraindicated. Their tough and explosive character traits are enhanced with such a talisman. As a result, a lot of troubles happen, life is turned upside down, and troubles pour in like a bucket.
As for the other representatives of the star circle, for them corundum is an ordinary decoration that does not have any energetic effect.
Wear jewelry correctly
A sapphire inserted into a pendant will relieve its owner from causeless anxiety, worry and hidden fears. For people wearing blue sapphire earrings, it will give wisdom and a harmonious attitude towards the world around them. In addition, a stone located in the head area enhances intuition, spirituality and develops a person’s existing talents. This applies equally to sapphire and ruby.
Lithotherapy specialists point out that the properties of corundum directly depend on the color.
- ruby enhances blood circulation and the work of glands that affect secretion;
- A stone of blue shades improves vision and normalizes eye pressure;
- The purple hue of the mineral accelerates recovery after concussions, increases resistance to stress, and relieves nervous conditions.
Intuitively, corundum is chosen by people with high efficiency, obsessed with their life's work. This mineral enhances the potential of workers and gives strength for new creative discoveries. Sapphires and rubies are recommended even for schoolchildren and students. Stones help in solving complex problems in exams and tests.
What does an ordinary resident of our state imagine when he hears the words “synthetic corundum”? Perhaps a comparison will come to mind with all sorts of trinkets made from glass, which have no value and are worth nothing. However, this is not the case.
What may be mistakenly considered a synthetic stone is, in fact, an absolute fake, that is, it is glass or plastic, which gives the appearance of a precious product. They are trying to present them as truly expensive stones, although they will not withstand even the slightest test of authenticity.
But synthetic stones are just absolute analogues of precious stones, the only difference is that they are created artificially. All the main characteristics inherent in real natural precious minerals, such as strength, structure, color shades, are almost exactly repeated in artificial stones. Naturally, the price of such creations is much lower than the prices of the originals, but they are still good in their own way.
Attempts to create artificial gemstones
The first attempts to recreate precious stones came down to a banal fake made from colored glass, and if you were lucky, from rock crystal. There were various attempts by learned alchemists in this direction. But it was only in 1892 that a huge breakthrough occurred in the stone synthesis industry. The world's first crystal of artificial ruby weighing 10 carats was grown in a laboratory setting by the French chemist M. A. Verneuil. It was this discovery that formed the basis for the industrial production of crystals. Thus, their use has become available not only for jewelry, but also in various technical fields.
Modern methods for producing artificial crystals are mainly based on the same Verneuil method, discovered more than 100 years ago. But now it is possible to create different types of stones only by making adjustments to the conditions of their “manufacturing”, that is, adjusting the temperature conditions and pressure value to suit the specifically required type of stone, and also using the appropriate chemicals to paint it a certain color. For example, from the widely available synthetic corundum, it is almost equally possible to create both a red ruby and a blue sapphire, all just by adding a suitable metal oxide in the process.
A unique synthetic method for creating artificial pearls. It is radically different from other methods, because here the “production” is performed by the mollusk itself. Human intervention consists only of the scientist implanting a small ball into the shell. The mollusk, as expected, envelops it in rainbow layers. To create a pearl of standard diameter, this animal will spend about 5-7 years. In general, nothing new, because this method of growing pearls has been used for more than 200 years in Asian countries: China, Japan.
What types of corundum exist in nature?
In nature, there are such types of corundum as:
- ruby (red stone, first category);
- sapphire (three colors: green – “oriental emerald”; blue – “blue yacht”; purple – “oriental amethyst”);
- leucosapphire (transparent colorless stone);
- padparadscha (color in yellow or orange-yellow tones);
- star ruby (stone with asterism effect);
- common corundum (color – gray shades).
What makes synthetic jewelry different? Now you can divide all synthetic stones into two types. The first group includes such “products” that are created in the likeness of materials already existing in nature: opal, ruby and other precious and semi-precious stones. the second group consists of new types of crystals (fianite, fabulite, etc.), synthesized by humans, which do not exist in natural conditions.
Synthetic stone is distinctive in that it is almost impossible to have flaws in it, because it is created according to a single rigid scheme in standard laboratory conditions, unlike natural stones, the creation process of which is individual in each individual case. Flaws in artificial minerals, which also in some way make them unique, can only arise from minor manufacturing defects. For example, a particle of the raw material may not melt, or an air bubble may become mixed in the stone cage. Using these features, jewelers can easily determine that stones were created in a laboratory.
How is artificial corundum created?
To create corundum in industrial conditions, bauxite ore is used. It is melted and recrystallized with an oxygen-hydrogen flame in electric furnaces, which also contains a reducing agent, which is iron filings. Depending on which element ions are added during the crystallization process, red (chrome), yellowish-pink (mangan), violet-pink (titanium) and other stones may come out.
Further, after cutting, synthetic corundums are given various names (amethyst, topaz, ruby, sapphire) and are used either in jewelry or in technology (for example, red corundums - in watches and other precision instruments). Synthetic corundum, which does not contain any additives, is widely used in radio electronics.
Confusion over the possibility of man-made gemstones
Suddenly it became possible to produce once unique natural minerals (unique and therefore precious) in the laboratory. The bewilderment of the jewelers was very great. However, the market eventually accepted synthetic corundums as an alternative and gave them its own slot on it.
Naturally, the price of artificial corundum is lower compared to the cost of natural ones. In individual cases, the difference ranges from units to hundreds of times.
Thus, a synthetic emerald can cost 2-3 times less than a natural emerald.
And diamonds are practically equivalent to, for example, diamonds mined in Africa or India. Their production technology in laboratory conditions is extremely complex due to the unique structure of the mineral, hence the corresponding cost. There are also minerals that are hundreds of times cheaper than their “natural brother”. Nevertheless, the price of any stone will undoubtedly be influenced by its characteristics, that is, size, quality of imitation, absence of flaws, quality of cut, and so on.
Thus, artificial stones have become an excellent alternative, but in no case a replacement for natural stones. It is unlikely that an ordinary person who decides to buy a diamond ring will think about whether it was made by nature or by a human hand. After all, this is not a piece of plastic that will lose its original appearance after a short time. This is a completely competitive, natural stone of its kind, having the same properties as a natural mineral, possessing the same beauty and splendor. Indeed, chemical reactions in the laboratory differ from natural ones only in that in the laboratory everything happens under the strict guidance of a person.
There are such amazing artificial jewelry that they rightfully occupy their rightful place on a par with the world's specimens of natural origin.
At the same time, the advantage and disadvantage of synthetic stone is its identity, relative cheapness and mass production. The feeling of the mystery that a natural mineral can instill in a person disappears. The mystery of nature, which created this indescribably beautiful and unique pebble for many years somewhere in the bowels of the earth.
The natural beauty of the corundum stone attracts the eye, and the magical and healing properties of the mineral evoke respect and admiration for its powers. This is not one gem, but a whole group of luxurious precious stones, including the famous rubies and sapphires. A wide range of colors, dazzling shine and transparency are the main reasons for the enormous popularity of the group.
From a scientific point of view, corundum is crystalline alumina. It is present in deposits in the form of several varieties, including expensive and unique sapphires and rubies. The name “corundum” comes from the word “kuruvinda”, which means “ruby” in Sanskrit. In the old days in Rus', stones were called yakhonts.
A group of minerals called corundum share the same physical properties, chemical composition and structure. Gems differ only in appearance and color, which depends on microimpurities of other substances in the composition - vanadium, chromium, iron or nickel.
Physical properties of the group:
- formula - AI2O2;
- syngony - trigonal;
- gloss - glass;
- density - 3.9-4.1 g/cm³;
- fracture - uneven;
- hardness - 9 units. according to the Mohs scale;
- transparency - full or partial.
In terms of hardness, the stone is in second place after diamond: on the Rockwell scale, this indicator is almost 90, which allows it to be used for sharpening tools and knives.
The crystal is resistant to acids and has high thermal conductivity. When heated, the color of the gem loses its saturation, and under radioactive influence it becomes brighter. The melting point is 2050 ℃, which allows the mineral to be used as a fire-resistant material.
Corundums are of igneous origin and are also found in igneous rocks and as a product of metamorphic processes. Gems are found in nests, veins and slates. The most expensive and noble specimens are mined in the form of crystals and pebbles in limestone and alluvial deposits.
Deposits of stones by color and quality:
- bright red rubies are mined in Burma and Thailand;
- High quality sapphires are found in Thailand and Sri Lanka;
- deposits of all kinds are located in Australia;
- deep blue sapphires are found in India and the USA, specimens with inclusions are found in Brazil;
- Low quality gems are mined in China, Colombia, Norway and on the island. Madagascar.
Varieties of corundum
All minerals included in this group have the same properties, but differ in colors and shades. Each variety is unique, and many of them are precious jewelry stones belonging to the first category.
Varieties:
- - transparent red corundum, with a rich scarlet tint due to the admixture of chromium in the composition. The color of the gem can vary from light red to dark cherry, and some specimens have a purple or brown tint.
- Sapphire- often a blue crystal, which contains titanium, which gives the stone the color of the sky. There are also other tones and shades: indigo, cornflower blue, soft blue and dark blue.
- - a gem with an amazing color transition from yellow to orange or pink.
- - a transparent crystal, externally identical to diamond.
- Pink corundum- a mineral with manganese impurities in its composition, due to which the color acquires a bright pink tint.
- Eastern emerald- corundum is a rich green color; due to its similarity with precious beryl (emerald), the stone received this name.
- Synthetic corundum- an artificially grown crystal, its properties are not inferior to natural ones. The color of the stone can be any.
- White gem- a mineral used in technology and industry.
- Emery- crystal with impurities of hematite and magnetite. Color - gray or dark gray with a black tint.
Eastern emerald
Pink corundum
Synthetic corundum
Magic properties
Since ancient times, corundums have been considered sacred stones that can help the owner in difficult situations and protect against the evil eye and damage. Talismans and amulets made from them were worn to protect against dark forces, and decorative items inlaid with stones were kept in the house to improve well-being and strengthen marriage bonds.
Corundum is an energetically active gem, therefore it is suitable only for purposeful and active people. For those who simply go with the flow, the mineral can be harmful.
Magical properties of crystals:
- calm nerves and put feelings and emotions in order;
- restore vitality;
- improve memory and attentiveness;
- increase the thirst for knowledge;
- help get rid of phobias and fears;
- give self-confidence;
- increase performance;
- endowed with purposefulness, determination and courage.
Medicinal properties
Humanity has known about the healing qualities of these natural stones since ancient times. Any corundum crystals have unique healing properties, but depending on the color and shade, each mineral specializes in a specific part of the body.
Healing properties of stones:
- Blood red rubies improve metabolism and blood circulation, and also normalize hormonal levels.
- Precious blue sapphire restores visual acuity, stabilizes ocular and intracranial pressure.
- Yellow-orange crystals improve the functioning of the gastrointestinal tract and slow down the aging process.
- Corundums with violet hues calm the nerves, relieve insomnia, depression and mental illness, and also improve mood.
All varieties, when worn for a long time, can relieve back and joint pain, lower blood pressure and improve the functioning of the kidneys and urinary system.
Meaning of zodiac signs
Natural corundum is not suitable for all horoscope signs - the crystal is especially suited to some, while for others it will bring failure and discomfort.
The influence of the stone on representatives of the zodiac circle:
- Taurus It is recommended to wear blue and blue corundums, which will improve intuition and creativity, protect against evil and negative energy.
- To Cancer Representatives of any colors and shades are favored. Gems will help you find love, establish connections with others, and improve your financial situation.
- Scorpios Minerals of red and pink shades are suitable. Stones of such colors will give the representative of the sign sociability, sensitivity and good mood.
- Aries You can wear gems of any color, but only after reaching the age of forty. The crystal will return them youth and excellent health.
- Aquarius Transparent or blue minerals will help you find peace of mind.
- Pisces White or colorless stones are ideal - they will bring good luck and family happiness.
Wearing the mineral is contraindicated for Capricorns, Leos and Geminis - corundum will not bring anything good to these signs. The strong “explosive” energy of the stone will make the already wayward representatives of the signs unpredictable and aggressive. Other signs can wear items with the mineral, but only as decoration, because crystals will not provide much assistance or assistance.
Application area
Thanks to its alluring shine and unique physical properties, the use of corundum in the world is diverse. Expensive transparent varieties - rubies and sapphires - are the material for making jewelry with stones. Before use, gems are cut: step, cabochon, diamond or mixed. The frame for the crystals is selected from noble metals - gold, silver or platinum.
When making jewelry, combinations are often created with other minerals: pearls, emeralds, garnets and diamonds.
In addition to the jewelry industry, gems are used in the following areas:
- in grinding machines as an abrasive material;
- in mechanical engineering as raw materials;
- in the production of watch glasses;
- for the production of lasers.
Corundum is a group of minerals with amazing properties, beauty, healing and magical qualities, which fully compensates for the high price of jewelry. Gems are suitable for purposeful, active people, but only natural stones, and not artificially grown crystals, will bring good luck and happiness.
Many people perceive them as the same stone. And this is not without reason. Both minerals have a glassy luster, have a pink-red hue, the stones are durable and resistant to acids and various chemicals. When examining corundum and ruby in detail, a logical question arises: what is the difference between both stones, which of them should be considered precious and which of the two will cost more?
Where are they mined?
It is believed that rubies were first discovered on the ancient continent of Pangea. As a result of natural processes, earthquakes and ground shifts, the continent collapsed, and all the precious mineral deposits were distributed over sections of the disintegrated territory: some remained to mature in the depths of the rocks, some broke off along with sections of the mainland, and were carried out to sea. It was this part that, when interacting with water, the minerals changed their color to blue, cyan, etc.
Today, corundum and ruby are mined in several large deposits: India, Ceylon, USA, Russia, Canada. Deposits of precious stones have also been discovered in Sri Lanka, Madagascar, Tanzania and Greece. The most valuable, and therefore expensive, are the minerals mined in the Asian part. Even in external parameters, such jewelry inserts look more transparent, crystal clear and shiny.
Application
Corundum and ruby are used not only to create decorative jewelry. Corundum, which is grown in laboratory conditions, has high value in the production of fire-resistant materials and high-quality coatings. Considering that rubies and corundums are second only to diamonds in their strength, these stones are actively used for industrial and construction purposes. They are especially important for sanding and grinding work.
What is the difference?
Today, jewelry with corundums is very popular in jewelry. And you can often hear that corundum is an analogue of ruby. Is this really true? The answer is ambiguous. In terms of characteristics, both minerals have many similarities. They have the same color, structure, shine, etc. But corundum stone is a more general name for minerals. It can be called the mineral base from which the future ruby is formed.
Scientifically speaking, corundum is crystalline aluminum oxide. This is a super-strong stone that is formed in rock deposits in the form of individual crystals or welded columns. In its pure form, corundum is an absolutely colorless mineral. Only under the influence of temperatures and natural impurities can it acquire different shades: white, blue, black, green, red, yellow. The main difference between corundum and ruby is color. Corundum can be of a wide variety of colors, ruby - only red. The scarlet or pink tint of a ruby depends on how much chromium impurities are in the corundum structure.
A subspecies of blue corundum is commonly called sapphire. Its color indicates that the structure of the stone contains an admixture of titanium.
The main difference between corundum and ruby is that ruby, due to its longer period of “maturation” and the presence of impurities in it, can be classified as precious stones, but corundum cannot. Also, knowing the process of formation of both stones, ruby can be called corundum, but not vice versa.