James Clarke Inc Diamonds

Famous Diamonds

Cullinan (3,106 carats uncut). Found in the Premier mine, South Africa, in 1905, and cut into 105 separate stones of which one, 530 carats, is the principal stone of the British royal scepter.

Excelsior (995 carats uncut). Found in the Jagersfontein mine in South Africa, 1893.

President Vargas (726 carats uncut). Found in Rio San Antonio in Brazil in 1938, and cut into 29 stones the largest of which is 48 carats.

Regent (420 carats uncut). Found at Partial in India in 1701, it was reduced to a single stone of 137 carats by successful cutting. It is now at the Louvre in Paris.

Orloff. Found in India at Kollur, and bought for Catherine II at the end of the 18th century. Cut weight is 199 carats.

Koh-I-noor. Indian stone known since 1304; its cut weight was 186 carats, but it was re-cut in 1852 to a stone of 108 carats.

Hope. The "Blue diamond" of 112 carats uncut weight was found in India at Kollur, bought by Louis XIV in 1668, and cut into a weight of 67 carats. It was stolen in 1792 and re-cut; the Hope diamond (44 carats) of the Smithsonian Institution is probably this stone.

Interesting Facts

Sparkle is a result of how the light enters, travels through and leaves the stone.

Diamonds and the graphite in your pencil are both exclusively carbon, yet have vastly different properties!

More Info

Stone History
Stone Science
Diamonds
Colored Stones
The 4 "C's"

Known in India since at least 1000 BC, the diamond is the hardest of all minerals. The word, diamond, takes its name from two Greek words – diaphanes, which means transparent, and adamas, which at first meant extremely hard, and now is the modern Greek word for diamond.
Diamonds have a range of colors, some of which the current fashion proves to be acceptable, and others are unacceptable as gems, but used commercially. The most perfect diamonds are without any fault or variation of color, yellowness or brownishness, which renders them less favorable. Some rare stones are golden-yellow or pale pink, blue-green or red; the clear colors are much sought after, particularly those of a blue-whiteness. Perhaps the rarest is the blue-green Ocean Dream. Found in central Africa, this 5.51 carat diamond's unique color is the result of exposure to natural radiation as a result of being buried in the earth for millions of years.

The diamond is the most important of precious stones and by itself it represents as much as 80% of the trade in gems and (taking into account the production of industrial diamonds which cannot be used in jewelry because of their opacity or bad color).

Of all the cuts, the brilliant cut is the most often used since it makes the most of the refraction colors that are the particular charm of this stone. Diamond cutting is complicated by the variations in hardness that are met according to the angle of the faces in relation to the axis of the crystal. The stone may only be scratched or cut by another diamond, or worked with diamond powder. Most diamonds are found in a basic igneous rock called kimberlite. It is in this rock that diamonds occur in Africa and Russia and it is assumed that all other deposits of diamond (alluvial deposits) had their origin in such rocks. Kimberlite is a basic lava which forms the famous diamond bearing "pipes" as it blocks volcanic chimneys caused by explosions below the earth's crust. Diamonds are also found in pre-Cambrian conglomerates, in grits, and most often in fairly old and redistributed alluvium (such as river sedimentation, marine shelves or sand banks).

The most unusual shape in which diamond crystals are found is the octahedron which consists of eight triangular faces. This shape lends itself very well to being cut in half, just above the center, and faceted into two brilliant cut stones. The brilliant cut was especially adapted for diamonds so that in a well-cut stone, all the light entering the tip of the stone would be refracted and reflected around the back facets and returned to the eye, thus displaying the well known brilliance of diamonds. The value of cut diamonds is determined by an international system of evaluation for simplicity's sake as "The Four C´s", or color, clarity, carat weight and cut. The most valuable are colorless diamonds, particularly those with a slight bluish tinge. The weight of diamonds is measured in carats, a standard weight equal to .20 gram.

A diamond is composed of pure carbon so it is actually graphite. The difference between the graphite and a diamond is found in the crystal structure which causes vast difference in properties of the two. Diamond is the hardest natural substance known while graphite (a component of pencil lead) is one of the softest. The diamond crystals have a considerably stronger cohesion which gives them a degree of hardness unequaled in the mineral kingdom. The majority of diamonds found display faint shades of color in an essentially colorless stone, although the best quality diamonds are completely colorless. Deeper shades of yellow brown, green also occur as do pink, deep blue and deep green although those colors are extremely rare.

The earliest sources of diamond were in India and these mines produced many of the large historically famous diamonds including the Koh-i-noor and the deep blue Hope diamond. The Indian deposits, which were the sole source of diamonds until the 18th century, yielded in excess of two tons (10 million carats). Diamonds were discovered in Brazil, near Rio de Janeiro in 1725 and in South Africa in 1867 and in Australia and Canada in the mid to late 1900's. Many areas in South Africa produce diamonds and it is one of the largest sources of gem quality stones.

Legend says that Agnes Sorel was the first woman to wear diamonds. According to tradition, she fell in love with King Charles VII of France, and wishing to attract his attention at court, she borrowed as many diamonds as possible from her men friends and relations. Up to this time, diamonds had been a masculine ornament. She then had the diamonds set into a necklace. Her first appearance at court produced a sensation, and she caught the king's eye.

However, the earliest surviving records have shown that Archduke Maximillian of Hamburg may have started the trend among the European wealthy and royalty of giving diamond engagement rings in 1477 by giving Mary of Burgundy a diamond betrothal ring. At that time, diamonds were looked upon as talismans, or charms, that could enhance the love of a husband for his wife. Even Cupid’s arrows were said to be tipped with diamonds, which had a magic that nothing else could equal.