Difference between corundum and ruby

Corundum and ruby ​​have a number of similar properties - both minerals have a glassy luster, both are acid-resistant and chemically stable. They are extremely durable due to the fact that there are no adhesions in them, therefore they can be used for abrasive processing. There are no perfectly pure rubies and corundums in nature, just as there are no ideal forms. All these are united by the mentioned minerals. But then what is the difference between corundum and ruby?


Corundum - crystalline aluminum oxide with uneven. The mineral is dichroic, dense and so hard that only diamond is harder than it. In nature, there are both individual minerals in the form of crystals, and accreted into "barrels" or columns. The natural colors of corundum are red, black, yellow, pink, white and green. And this is the first difference between corundum and ruby, which is only red or red shades.

Among the varieties of corundum are sapphire (blue, green, purple), leucosapphire, ruby, padparadscha, amethyst.

As for ruby ​​, the more chromium impurities it contains, the thicker its red color. If you shine ultraviolet light on the stone, it will turn orange. Rubies can be obtained artificially (for the first time the Frenchman Auguste Verneuil succeeded in 1904), such samples are sometimes called spinels.

There is a theory that rubies are immature sapphires. After the collapse of Pangea (the ancient single continent), one large deposit collapsed. Some of the rubies remained in the rocks of the earth, where the stones under pressure continued to be saturated with metal oxides and “turned red”. Another part went on a journey across the oceans and rivers, "blue" and "yellow" along the way.



Corundum and ruby ​​are mined from rocks with a low silica content, from pegmatites and deep metamorphic rocks - gneiss and granulite. The mixture of corundum and magnets can be part of emery or emery layers. Corundum is mined in India and Greece, Sri Lanka, Ceylon and Madagascar, the USA, Tanzania, Canada, Norway and Russia. The most valuable rubies are Asian, as they are the purest and most transparent. These stones are mainly mined in Sri Lanka and Thailand, as well as in Tanzania - in these areas there are reference samples of the color of "pigeon blood".


Corundum obtained by artificial means is indispensable in the manufacture of refractory materials, high-strength enamels, abrasive compositions. A separate type of corundum is electrocorundum - a superhard artificially synthesized material extracted by high-temperature melting of bauxite. Electrocorundum is used for grinding especially strong materials. Ruby is used for making jewelry, watch mechanisms. Synthetic rubies are needed in lasers (the technology was first tried out in 1960).

Corundum is popular in folk medicine for improving blood circulation and metabolism, treating eye diseases, and normalizing digestion. Ruby, according to legend, helps its owner to find and maintain love, makes the mind discerning and rejuvenates the body.

Corundum Ruby
Metallic or mattShine only metallic
It happens not only red, but also white, and green, and other colorsIt happens only red and all of its shades
Mostly opaqueMostly transparent

So, the main difference between corundum and ruby ​​is that that the latter is a gem and the former is not. Moreover, the ruby ​​itself is a kind of corundum, and therefore ruby ​​is the same as corundum, but not vice versa!