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Wednesday, February 20, 2008

How Diamonds Made

Diamonds form between 75-120 miles below the earth's surface. According to geologists the first delivery of diamonds was somewhere around 2.5 billion years ago and the most recent was 45 million years ago. The carbon that makes diamonds comes from the melting of pre-existing rocks in the Earth's upper mantle. There is an abundance of carbon atoms in the mantle. Temperature changes in the upper mantle forces the carbon atoms to go deeper where it melts and finally becomes new rock, when the temperature reduces. If other conditions like pressure and chemistry is right then the carbon atoms in the melting crystal rock bond to build diamond crystals.

There is no guarantee that these carbon atoms will turn into diamonds. If the temperature rises or the pressure drops then the diamond crystals may melt partially or totally dissolve. Even if they do form, it takes thousand of years for those diamonds to come anywhere near the surface.

It takes millions of years to make a diamond. When you own a diamond, you own something which is a legend in the making. It has not been made in a factory just the other day. A diamond comes from the bosom of the earth. More interestingly not all the diamonds mined are made into jewelry. Only one fourth of the diamonds that are mined are made into jewelry. Every 100 tons of mud produces one carat of a diamond. And this one carat is not one stone! It could be anything from 0.005 ct to 1 ct. because much of the original stone is cut away in the process of cutting, shaping and polishing the diamond.

Diamonds come in different rough shapes. The next time you look at your diamond, think about the amount of time, energy and resources that have gone into making that one precious stone.

De Young Red

De Young Red, a 5.03-carat, brilliant cut red diamond. The main kite-shaped facets on the crown are divided in two, giving the stone more brilliance than a standard round brilliant cut. The stone is not pure red but has a slight brown hue, which makes it appear like a fine red garnet and indeed, it was once purchased as such at an estate sale.

It is the third largest red diamond in the world, after the Moussaieff Red (5.11 carats) and the Red Diamond (5.05 carats).

Monday, February 18, 2008

Shepard Diamond

Other colored diamonds in the Smithsonian Collection include the 8.30-carat Shepard Diamond.

This stone is from South Africa, and was acquired by the Smithsonian Museum in exchange for a collection of small diamonds that had been seized as smuggled goods by the United States Customs Service. The diamond is named for the Smithsonian employee who helped facilitate the transaction.


Appreciation -
Picture courtesy from famousdiamonds.tripod.com

Thursday, February 14, 2008

Victoria Transvaal Diamond

The Victoria-Transvaal is a 67.89-carat, brownish-yellow pear shaped stone. It was cut from a 240-carat crystal that was found in the Transvaal, South Africa. The first cutting produced a 75-carat 116-facet stone that measured 1 x 1³/8 inches; a recutting retained the same length and width, but reduced the depth to better proportions, making it more brilliant. The diamond has been featured in several Hollywood films, including a Tarzan episode from 1952 titled Tarzan's Savage Fury, and in leading exhibitions in the United States and Canada.

The necklace was designed by Baumgold Brothers, Inc, and consists of a yellow gold chain with 66 round brilliant-cut diamonds, fringed with ten drop motifs, each set with two marquise-cut diamonds, a pear-shaped diamond, and a small round brilliant-cut diamond (the total weight of the 106 diamonds is about 45 carats). The configuration of these stones makes them look like small angels! The necklace was donated by Leonard and Victoria Wilkinson in 1977 to the Smithsonian Institute, Washington D.C.


Appreciation -
Picture courtesy of www.historywiz.com

Wednesday, February 13, 2008

All About the Clarity of Diamonds

Clarity is an important aspect of a diamond, and it is important to know how to grade the clarity of a diamond before you buy one. It is actually quite easy to learn how to grade the clarity of a diamond. There are basically two things that you must understand: Diamonds with visual inclusions and blemishes, and those that are ‘eye clean’ meaning that there are no inclusions or blemishes that can be seen with the naked eye. From there, the clarity of a diamond is further broken down into subcategories.

Many people mistakenly think that diamond clarity refers to how clear it is. This isn’t so. Clarity actually refers to the internal and external imperfections of the diamond. The best diamonds, of course get a grade of FL or IF – Flawless or Internally Flawless – meaning that it is perfect. A grade of I-1, I-2 or I-3 means that the diamond is imperfect, with a grade of I-3 being the worst.

Other grades are VVS1 and VVS2, which means that the diamond is very, very slightly imperfect; VS1 and VS2, meaning the diamond is very slightly imperfect; SI-1 and SI-2, which means that the diamond is slightly imperfect.

Spanish Inquisition Necklace

One doesn’t normally associate beautiful jewelry with the time of the Spanish Inquisition. But in the Smithsonian Institution’s collection of gems, there is an exquisite necklace of diamonds and emeralds.

It is a spectacular double row of diamonds and emeralds ending in a chandelier of emeralds. There is unfortunately very little information about the provenance of this necklace. The large diamonds and Columbian emeralds were most likely cut in India in the 17th century. This would make them one of the earliest examples of cut gemstones in the Smithsonian’s Collection. There are really only legends surrounding this necklace. They indicate that it was worn at times by Spanish and French royalty. In the early 20th century, it was purchased by the Maharajah of Indore, whose son sold the necklace in 1947 to Harry Winston. Winston subsequently sold the necklace to Mrs. Cora Hubbard Williams of Pittsburgh. She bequeathed it to the Smithsonian in 1972.

Emeralds are a form of crystal known as beryls. Beryls are normally clear crystals, but when infused with chromium or vanadium, they attain various gradations of green. The purest green are the rarest emeralds and many people actually prefer an emerald that has a blue-green tint.

Before the 16th century, the only known emerald deposits were in Cleopatra’s Egyptian mines. But after emeralds were discovered in Columbia, those became the “gold standard” in emeralds. Columbian emeralds have been discovered by archaeologists among artifacts of such tribes as the Inca, Maya, Aztec, Toltec and the lesser-known Chibcha Indians. Emeralds are among the rarest of gemstones and can be more expensive per carat than even the finest diamonds! They are a hard mineral, with a Moh’s hardness scale of 7 or 8 (compared to a diamond’s 10). While most emeralds are found in Africa, Russia and Africa, there have been discoveries of emerald deposits in North Carolina!


Appreciation -
Image source:
www.gimizu.de

Tuesday, February 12, 2008

Smithsonian Collection

Some of the world’s most spectacular diamonds and other gems are located in the National Gem Collection in the Museum of Natural History in Smithsonian Collection in Washington, D.C. In the collection are diamonds known to almost everyone, such as the Hope Diamond, as well as other large diamonds and other precious gems and jewelry.

In the National Gem Collection are examples of spectacular minerals and crystals, as well gemstones and jewelry. You can see a beautiful purple quartz amethyst crystal, or the mineral azurite, which is a bright blue copper compound mineral. You can also see a huge green beryl crystal. Beryls are the mineral family that include emeralds, aquamarines, heliodor and morganite. It’s almost as exciting to see the raw crystal as it is to see the finished product when it’s been cut and polished.

Some of the finished pieces in the Smithsonian Collection include the crown Napoleon used for the second Empress, Marie Louise. It originally was made of 700 carats in diamonds and 79 emeralds. The emeralds have been replaced with Persian turquoise cabochons.


You can also see the 182-carat Star of Bombay star sapphire that was given to Mary Pickford by Douglas Fairbanks and a brilliantly colored black opal. Black opals are the most valuable of the opal family of gems.


There are also extraordinary examples of quartz crystals, including a 7,000 faceted clear quartz egg! Part of the Smithsonian’s collection includes pieces of jade and turquoise used in other cultures. This includes a collection of Zuni Indian turquoise jewelry and jade lanterns carved from nephrite for the Chinese emperor Chi’en Lung in 1750. A more modern piece is the Dragon Vase, carved from a rare piece of lavender jade.

But of course, the most dazzling items in the collection are the individual gemstones and jewelry that have been owned by royalty through the centuries.