A variety of corundum mineral like sapphire, ruby is a precious stone (like diamond, sapphire and emerald). This intensely red stone is sapphire’s cousin in terms of chemical composition and structure. They are the most expensive colored stones in the world, and the best pieces can rival diamonds. The brilliant red color of ruby is linked to its formation, which Planetys invites you to discover.
The origins of ruby
The name “ruby” comes from the Latin ruber, meaning “red”. The first rubies were mined in Sri Lanka in the 8th century BC. Today, the main ruby extractors are Mozambique, Thailand, Sri Lanka and Myanmar (formerly Burma), which was the world’s leading producer. The Mogok Valley is home to the world’s rubies, including the famous “pigeon’s blood” rubies.
However, centuries of over-exploitation of Burmese mines have made it more difficult to find new deposits of multi-carat rubies. The world’s new ruby production comes from Mozambique, Thailand and Sri Lanka. There are ruby specimens with asterism (cat’s-eye). Rare star rubies are sometimes found with the same properties and characteristics as ordinary crystals.
The red color of a ruby varies according to the stone’s deposit. Myanmar rubies, for example, are deep red with a slight bluish tinge. Rubies from Thailand, on the other hand, are often deep red with a brown tinge. Sri Lankan stones are strawberry-red. Kenyan and Tanzanian rubies have a superb, slightly orange-red color. Sometimes, however, rubies of different colors can be found in the same place. It is therefore impossible to determine the precise origin of the red-coloured stone.
How are rubies formed?
Symbolizing desire, passion and power, the ruby is considered the most precious stone in the world. Even a diamond would seem an ordinary stone compared to the unrivalled value and beauty of this brilliant red gem. In fact, ruby has all the characteristics of a precious stone:
- magnificent color,
- perfect hardness (9 Mohs),
- unique brilliance.
What’s more, ruby is an extremely rare gem, especially at its finest. After diamonds, rubies are the hardest and most resistant stones in the world. These jewels come from the same mineral family, aluminum oxide (corundum). Rubies are created by high heat/temperature and pressure in the bowels of clay-rich limestone. Rubies form mainly in metamorphic rocks and igneous or basaltic volcanic rocks.
Secondly, this precious stone is found in alluvial deposits. When the mineral corundum contains traces of chromic oxide (III), it transforms into ruby (chromium). This allochromic hue is responsible for ruby’s deep, highly saturated red color. If iron and titanium are the main chromophores in corundum, it becomes sapphire.
Ruby often has inclusions that are not considered defects. On the contrary, these impurities allow us to determine the gemstone’s natural origin. The mineral’s color is linked to a mixture of chromium. It takes on shades of deep pink to deep red with a violet tint. The world’s most prized rubies (especially in jewelry-making) are the “pigeon’s blood” colored stones. This is a unique red with a slight violet tint. Minerals with a brown hue are the least valuable.
