First and foremost, rubies often contain inclusions, which means that this gemstone, which has a hardness of 9 on the Mohs scale, has different optical characteristics. There are also rubies with asterism (the appearance of a shimmering star on the surface of a cabochon-cut ruby) or chatoyance (“cat’s-eye” effect). This effect is the result of acicular and parallel rutile inclusions on which light is reflected, and which appear mainly on cabochon-cut polished stones. 6-pointed stars are the most common, but 12-pointed stars are also possible. Planetys invites you to discover all existing ruby varieties.
Tanzania ruby
Ruby is a variety of the mineral corundum. What’s more, it’s a precious stone in the same way as diamonds, emeralds and sapphires. If you’re looking for sumptuous rubies, you’ll find them in this country known for its famous tanzanite.
Intense ruby color in Tanzania
The oldest ruby production sites in Africa are in Tanzania. The excellent reputation of these rubies is linked to the quality of the stones produced in the 1950s in the Umba River valley in the north-east of the country. Tanzanian rubies are extremely beautiful, with a deep, intense red color. A pronounced red color with a slight orange hue. They tend towards the shade of pigeon’s blood rubies, the cost of which is very high.
AAA-quality Tanzanian rubies
Unlike diamonds, colored stones such as sapphires, rubies and emeralds have no standardized, internationally recognized system for comparison. Certification of a colored stone like ruby is just as rigorous as for diamonds, and corresponds to several levels of quality:
- A, average and common quality,
- AA, rarer and superior quality, with few defects and pronounced colors,
- AAA, the best quality available for colored gems.
AAA-rated Tanzanian rubies are therefore stones of exceptional quality. These gems are characterized by superior brilliance, a total absence of flaws and pronounced, harmonious colors. This greatly justifies their cost.
The Kenyan ruby
Kenya is home to some of the most beautiful rubies in the world, with fuchsia-pink colors. The quality of Kenyan rubies is comparable to that of Mozambique rubies. Some of these colored stones can reach 20 carats, a weight virtually impossible to find in other mines. Like Tanzanian rubies, whose characteristics are very similar, Kenyan rubies have a beautiful red color and crystallization.
Orissa rubies
In India’s Orissa region, rubies are mined for their ornamental beauty. In the Orissa mine, you’ll find the most beautiful natural star rubies, with their impressive asterism. If you’re a fan of optical effects in gemstones, of captivating effects for the eye, you’ll be seduced by jewelry set with Orissa rubies. The color of this ruby is extremely violet, with dark red tones.
Intense Mozambique ruby
In just a few years, Mozambique has become one of the world ‘s leading ruby producers. Its production is gradually replacing that of Myanmar, which is steadily declining. This country produces the majority of rubies used in jewelry and haute joaillerie, mainly stones of 2 carats or more.
Mozambique rubies
This African country produces some very beautiful stones. Its rubies have a deep, intense red color. These red crystals blend particularly well with diamonds, enabling jewelers to create stunning jewelry pieces such as rings, earrings and more.
Mozambique star ruby
This ruby has the same optical characteristics as the Orissa star ruby, but is redder in color.
Mozambique cat’s-eye ruby
This ruby is a magnificent stone. When cut into a cabochon, a magnificent cat’s-eye effect is visible on the surface of this red gem.
Vietnam ruby
They were discovered in the mid-1980s. Until then, this region of the world was not renowned for its gem-rich resources. Vietnamese rubies are similar to rubies found in Myanmar, but are often of greater purity and intensity. The first rubies were discovered at Luc Yên, northeast of Hanoi. Other deposits were later discovered at Quy Châu, in the province of Nghê An. Vietnamese rubies are characterized by a pinker color than other African ruby varieties. Vietnam produces another gemstone, sapphire, which is generally dark blue.
Star ruby
Star rubies have an asterism. When placed under an electric light, a six-pointed star can be seen on the gem’s surface. What causes this phenomenon is nothing more than the reflection of light on the inclusions. These are fine needles of titanium dioxide spread out parallel along three axes that meet at 120° in the stone. To reveal a crystal’s asterism, it must be cut as a cabochon. Like all star gems, the most coveted rubies are those whose star is not only whole, but well centered on the stone, and whose star is as fine and precise as possible.
Top-quality star rubies are extremely rare. It is very difficult to find an intense red gem with a beautiful star. The vast majority of stones on the market are pink to purple in color, and asterism is extremely diffuse.
These stones cannot be heated to improve their color, as heating can dissolve the rutile inclusions, causing the star to disappear. Prices for the finest star rubies can reach tens of thousands of euros per carat. The most abundant production sites for star rubies are in Sri Lanka, Thailand, Afghanistan, Vietnam and Mogok in Burma (Myanmar), where, as with faceted rubies, the finest specimens come from.
