Roger Weller, geology instructor
Gemstones are naturally occurring precious or semi-precious stones that can be cut and polished and set in jewelry. The characteristics of the gem determine their value. Famous gemstones are valued for their size and beauty, and are larger and more expensive than something you could buy at even the most expensive shops in the world. Let’s start with breaking down the different kinds of gemstones and what they are famous for.
The diamond is the only gemstone made completely out of one element, carbon. On the hardness scale, a diamond is 10. About 130 million carats are mined every year with an annual total of nearly $9 billion, which make the next examples of famous diamonds even more extraordinary.
The Hope Diamond is a 45.52 carat deep
blue diamond and weighs about 112 carats. Legend has it the diamond was taken
from an idol of a Hindu goddess, which started the idea of a curse. The diamond
was cut from a much larger blue diamond called the Tavernier Diamond, which was
then cut again into the French Blue that became part of the French crown jewels
until the time of the French Revolution when it suddenly disappeared. A large
blue diamond similar in shape to the French Blue later became in possession of
the Hope family and was put up in display in London in 1851. The diamond was
past down the Hope family line until bankruptcy made the diamond up for auction.
It then came into the possession of Pierre Cartier. Cartier offered the diamond
to a socialite named
Evalyn Walsh McLean in 1910. McLean rejected it at
first, but eventually bought it anyway. After she died in 1947, her relatives
sold the diamond to Harry Winston. Winston donated the Hope Diamond to the
Smithsonian Institution on November 10, 1958 where it still is today.
The Centenary Diamond
The De Beers Centenary Diamond is the third largest diamond to have ever been produced in the Premier Mine. The Premier Mine, also called the Cullinan Diamond Mine, is a major underground diamond mine in South Africa. The stone has never been publicly appraised for its value, but its known to be insured for over $100 million in 1991.
Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6). They are colored green by trace amounts of chromium and vanadium, and have a hardness level of 7.5- 8.
The Mogul Emerald is one of the largest emeralds in the world. It weighs 217.80 carats and is about 10 cm high. It dates back to 1695, and is thought to have come from one of the last rulers of the Mogul dynasty in India. One side is engraved with Islamic prayers, and the other side is engraved with flower ornaments. The emerald was auctioned off to an anonymous bidder in London for $2.2 million in 2001.
The Chalk Emerald
The Chalk Emerald is considered one of the finest Colombian emeralds, and is 37.83 carats. It originally weighed 38.40 carats, but was later cut down into a ring by Harry Winston, and is surrounded by 60 pear shaped diamonds. Mr. and Mrs. O Roy Chalk donated it to the Smithsonian in 1970 where it still sits today.
An opal is a mineraloid gel that is deposited at a low temperature and occurs in fissures of almost any kind of rock. They are commonly found with sandstone and basalt.
(R.Weller/Cochise College) (R.Weller/Cochise College)
The Aurora Australis is the world’s most valuable black opal. It was found in 1938 and weighs 180 carats. The opal was dug from a dried seabed and has a distinctive starfish impression on its back. In 2005 it was valued at AUD$1,000,000.
The Olympic Australis is reported to be the largest and most valuable gem opal ever found. It weighs 17,000 carats and is 11 inches long. It was found in 1956 in the famous Eight Mile opal field in Southern Australia. It consists of 99% opal with the remaining 1% being soil that is still attached to the stone. It was valued at AUD$2,500,000 in 2005.
Rubies are pink and red-colored gemstones made from aluminum oxide. The red color comes from the presence of chromium. Rubies have a hardness level of 9. Another type of ruby is called star rubies. Star rubies have an asterism, an optical phenomenon that enhances the reflective surface of the gem and causes a star like pattern, thus the name “star ruby.”
Ruby Star Ruby
(R.Weller/Cochise College) (R.Weller/Cochise College)
The Delong Star Ruby
The Delong Star Ruby is a 100.32 carat star ruby that was found in Burma in the 19th century. It became famous in 1964 when it was stolen, along with the Star of India. The thief, a man who liked to be called Murph the Surf, ransomed the two jewels at $25,000. Both jewels were then recovered at a designated drop site, a phone booth in Florida.
The Mandalay Ruby is a 48.019 carat, cushion cut ruby that is almost flawless. Its intense red color, which is extremely close to the pigeon blood color that is more valued than regular colored rubies, is one reason why this ruby is so valuable. So valuable in fact, that Sotheby’s auction house in New York City valued it at a pre-sale value of $15 million in 1988. Surprisingly, it received no bids. Its origin is unknown and no one can seem to figure out exactly where it came from, but either way, the Mandalay is considered one of the finest rubies in the world.
The Mandalay out of its setting
A sapphire is a gemstone made out of a variety of the mineral corundum. Sapphires come in every color except red, because if it is red, it is called a ruby. Trace amounts of other elements such as iron and titanium give sapphires its other colors. Sapphires also have asterisms, making them “star sapphires.”
R.Weller/Cochise College R.Weller/Cochise College
The Star of India
The Star of India is the largest and most valuable star sapphire in the world. It is 563.33 carats and was formed about 2 billion years ago. The sapphire was stolen, along with the Delong Star Ruby, but was recovered from a phone booth in Florida and was returned to the New York Museum of Natural History, where it still is today.
Queen Marie of Romania’s Sapphire
The Queen Marie of Romania’s
Sapphire out of its setting
This gemstone is a giant cushion-shaped sapphire weighing in at 478.68 carats. In 1919, it was Cartiers most valuable sapphire and was purchased for Queen Marie of Romania by King Ferdinand two years after the Spanish exhibition. Somehow, it became in possession of Harry Winston who set it in a
platinum pendant. In November of 2003 it came up for auction and sold for 1,916,000 Swiss francs, which is equal to $1,494,480.
The Queen Marie of Romania in its setting
There are more famous gemstones of the world of course, but to me, these were the most interesting and the most beautiful. If you would like to find out what other gemstones are out there, just do some research.