The World's Rarest Gems - part 2

Continuing the list of the world's rarest gems, here are 5 more:

5. Alexandrite

Named for Tsar Alexander II of Russia, this exceedingly rare gemstone was thought to be mined out after the original deposits, found in 1830 in Russia's Ural Mountains, were nearly exhausted.

Alexandrite is a color-changing gemstone: its hue shifts from red to green depending on the light it's exposed to. Alexandrite from the Ural Mountains in Russia can be green by daylight and red by incandescent light. Other varieties of alexandrite may be yellowish or pink in daylight and a columbine or raspberry red by incandescent light.
Stones that show a dramatic color change and strong colors (e.g. red-to-green) are rare and sought-after.

Recent finds in Brazil, East Africa and Sri Lanka have brought this stone back on the market, but it is still one of the world's most coveted stones.

Today, several labs can produce synthetic lab-grown stones with the same chemical and physical properties as natural alexandrite. One of these methods produces what is called flux-grown alexandrite, which produces gems that are fairly difficult to distinguish from natural alexandrite as they contain inclusions that can look natural.

Composition: Beryllium, Aluminum, Oxygen | Market Value: $12,000 per carat.

4. Blue Garnet

Although red is the most commonly occurring colour, garnet occurs in almost every colour. One of the most recently discovered colours of garnet is the rare blue garnet, which was discovered in the late 1990s in Madagascar. It has since been found in other regions, such as the USA, Russia, Kenya, Tanzania and Turkey.

It changes color from blue-green in the daylight to purple in incandescent light, as a result of the relatively high amounts of vanadium. The most expensive, a 4.2 carat gem sold in 2003 for $6.8 Million.


3. Musgravite
Another precious stone in the same family as Taaffeite, this stone's color ranges from a brilliant greenish gray to purple. Musgravite was discovered in 1967 in the Musgrave Range of Southern Australia, and for many years there were only eight known specimens.

Recently, small quantities of Musgravite have been located in Greenland, Antarctica, Sri Lanka, Madagascar and Tanzania. Don't let this new "surplus" fool you, though: this incredibly hard stone is still exceedingly rare, fetching $35,000 - or more - per carat.

Composition: Magnesium, Beryllium, Aluminum, Zinc, Iron, Oxygen | Market Value: $35,000 per carat. Its hardness is 8 to 8.5 on the Mohs scale.

2. Red Diamonds
Technically speaking, red diamonds are diamonds, but they serve to highlight the fact that that diamonds actually come in a range of colors. They are, in order of rarity: yellow, brown, colorless, blue, green, black, pink, orange, purple and red. In other words, The clear diamonds you're liable to encounter at your local jeweler aren't even rare as far as diamonds go.

As a point of reference, the largest red diamond on Earth — The Moussaieff Red, pictured here — weighs just 5.11 carats (about 1 gram). The largest traditional diamonds — such as those cut from the 3,106.75-carat Cullinan diamond — weigh in at well over 500 carats. [Photo Credit: The Gemological Institute of America]

1. The Pink Star Diamond

The Pink Star, formerly known as the Steinmetz Pink, is a diamond weighing 59.60 carat (11.92 g), rated in color as Fancy Vivid Pink by the Gemological Institute of America. The Pink Star was mined by De Beers in 1999 in South Africa, and weighed 132.5 carat in the rough. The Pink Star is the largest known diamond having been rated Vivid Pink. As a result of this exceptional rarity, the Steinmetz Group took a cautious 20 months to cut the Pink. It was unveiled in Monaco on 29 May 2003 in a public ceremony.

The Pink Star was displayed (as the Steinmetz Pink) as part of the Smithsonian's "The Splendor of Diamonds" exhibit. In 2013 the Pink Star was auctioned by Sotheby's in Geneva on 13 November 2013. The sale price was USD 83,187,381, a world record for a diamond of any colour and, indeed, for any gemstone.