Girl's Best Friends, Diamonds

DIAMONDS

THE GIRL’S BEST FRIENDS

Diamond, a precious stone composed of pure carbon. It is valued both for its beauty as a gem and for its industrial uses. Generally found as colorless stones, diamonds may also occur in tints of blue, green, black, light yellow, straw, brown, pink, or orange. All diamonds are crystals, most of them having eight sides arranged to form a double pyramid. However, some diamonds have only six sides, while others may have 12. The diamonds is the birthstone for April and is said to signify innocence.

Diamond is the hardest natural substance known. It can be scratched only by another diamond. It will not dissolove in any known liquid, nor can it be melted by heat. It will however, burn like a piece of coal when it is ignited in oxygen at a temperature of about 1800 °F., a diamond will crumble into graphite.

Diamonds were formed millions of years ago by pressure and heat. Synthetic diamonds, identical in virtually every way to natural diamonds, can be made by subjecting carbon materials to pressures of about 1,000,000 pounds per square inch at temperatures up to 5000 °F. Another man –made substance, a boron-nitrogen compound called borazan, is similar to diamonds in many ways, and is equally hard. Synthetic diamonds and borazan, both developed in the 1950’s have in dustrial uses but are ordinarily not suitable as gems.

Diamonds are weighed by the carat, just as sugar is weighed by the pound and coal by ton. One carat is equal in weight to 200 milligrams, or approximately.007 ounce.

Uses of Diamonds

Diamonds are valued as gems because they are rare and because they are bend, or refract, light to a greater degree than any other gem. This refraction causes light rays entering many colors. But the importance of diamonds is not confined to their beauty or value as jewelry. Because of their hardness , diamonds are widely used in industry for cutting, grinding, polishing, and scraping operations . About three-fourths of all diamonds (by weight) are put to such uses.

Diamond dust is used by jewelers to cut and polish other diamonds.
Sharp diamonds are used to cut glass. Diamond dies are used in making wire. Pointed diamonds are used to engrave on glass and steel. When set in a lathe, diamonds may be used to grind lenses. Cheaper grades of diamonds provide cutting edges for earth drills and rock-cutting saws. In the home , diamond tipped phonograph needles provide at least 10 times the wear of less expensive needles.

Where diamonds are found

Diamonds are widely distributed in nature. Until the 18^th century most diamonds were found in India and Borneo. In 1727 the great Brazilian mines were discovered. Brazil led the world in production until about 1800, when the supply of gem diamonds began to dwindle.

The world’s richest diamond fields were discovered in Africa in the 1860’s ,and today more than three-fourths of the world’s supply comes from that continent. South Africa and South West Africa are the chief sources of gem-quality diamonds, and also produce significant amounts of industrial diamonds. The mines near the South African cities of Pretoria and Kimberley have produced more fine diamonds than any other location on earth. The world’s largest single producer of industrial diamonds is Zaire (formerly Congo [Kinshasa] ). Other important diamond – mining nations of Africa include Ghana, Angola, and Sierra Leone.

Outside Africa , the only important source of diamonds is in the central Siberian region of the Soviet Union, where most of the output is of industrial quality. In the United States, diamonds have been found in several widely scattered locations. One site, in south-western Arkansas near the town of Murfreesboro, has yielded several thousand stones. A few diamonds have been found in other states, including California, Oregon, Wisconsin, and Kentucky.

Diamonds may be found as pebbles in sand and clay, or they may occur as crystals buried deep beneath the earth’s surface. Diamonds are often recovered from alluvial (stream-formed) deposits by simple washing. Underground diamond crystals are usually found in a type of rock known as kimberlite , which often occurs in tubular formations called diamond pipes. Depending on its depth , the kimberlite is extracted either from open pits or from underground mines. After mining, the diamond crystals are separated from the rock by screening, crushing , and washing.

The Diamond Industry

At one time India was the great gem-cutting and market center of the diamond industry. By the 1800’s Amsterdam and Antwerp had become the major clearinghouses for diamonds. They were joined after World War II by New York City , which now handles more than half of all the diamonds cut and sold each year throughout the world.

The cutting and polishing of diamonds is called dressing. One of two processes is used : sawing or cleaving. Most diamonds are sawed. The rough stone is cut to a desired shape by a thin, rapidly revolving disc that has been coated with diamond dust and olive oil. In cleaving , a steel blade is placed against a natural groove in the diamond and struck a hard , sharp blow. The stone cracks along the line of the line of its grain. The faces of the split stone are then polished by whirling steel discs fed with diamond dust and oil.

Diamonds may be sawed or cleaved into many different shapes.(see illustration.) The top of the diamond usually forms a fairly large flat surface, But

The sides and bottom are generally cut into dozens of small flat surfaces called facets. Light entering through one facet is refracting quality of the gem makes the light scatter, causing the diamond to give off a sparkling, many – colored light. This effect is increased by increasing the number of facts.

The value of a gem diamond depends upon its weight, the way in which it is cut , its color , and its purity. A pure diamond is one without flaws –cracks , pores, or deposits of foreign material or uncrystallized carbon .

See also ABRASIVE: BORAZON: CARBON: GEM : MINING (Illustration).

Diamond Head , an extinct volcanic crater rising 761 feet on the southeastern shore of the island of Oahu, Hawaii. It is a National Landmark and one of Hawaii’s most famous features. Diamond Head is on the outskirts of Honolulu near Waikiki Beach. Ancient Hawaiians used the crater as a burial ground. A lighthouse and Fort Ruger are on a plateau of Diamond Head.

Diamond Necklace, The Affair of the , a notorious scandal in the court of Louis XVI of France. Cardinal de Rohan was persuaded in 1784 by the so-called Countess Jeanne de la Motte and Count Alessandro di Cagliostro that he could win the affections of Queen Marie Antoinette if he bought for her a certain necklace of 500 diamonds. Although he did not know it, de Rohan was being used in a plot to steal the gems .

De Rohan was arrested in 1786 with the plotters and was acquitted, but exiled from court. Cagliostro also was acquitted , but the countess received a prison term. The affair figured prominently in misconduct charges made against the queen by her executioners in the French Revolution. Alexandre Dumas’ novel The Queen’s Necklace (1849) is based on the incident.

SOME FAMOUS DIAMONDS.

The Cullinan (3,106 carats, or 1.3 pounds), was the largest diamond ever found. It was taken from a Transvaal, South Africa, mine in 1905. The Transvaal government presented it to King Edward VII of England in 1097. In 1908 the diamond was cut in to 9 large and 96 smaller stones. The largest of these , Cullinan I , or Star of Africa, weights 530 carats and is the largest cut diamond in the world. It is part of the British crown jewels.

The Great Mogul Diamond (originally about 800 carats) was the largest Indian Diamonds . Unskillful cutting reduced its size to less than 300 carats. It disappeared after 1666 and has not been seen since.

The President Vargas (726.6 carats) was the largest diamond from the Western Hemisphere. It was discovered in Brazil in 1983 and was cut into 29 stones.

The Kohinoor (originally 186 carats, now 106) is said to have been stolen from an Indian rajah in 1304. The British East India Company obtained it in the 19^th century and gave it to Queen Victoria. The diamond is among the British crown jewels.

The Pitt or Regent, Diamond (originally 410 carats, now 143.2), like many famous diamonds, is shrouded in legend. It was discovered in India in 1701 and was said to have been stolen by a slave who used it to gain freedom. The diamond eventually came into the hands of Sir Thomas Pitt, a British official, who sold it to France in 1717.

The Orlov Diamond (199.6 carats, as cut) is owned by the Soviet Union. Discovered in India, it was first owned by Shah Jahan (builder of the Taj Mahal). The diamond was seized by Persian invaders in 1739 and reappeared some 30 years later in Amsterdam, where it was bought by Prince Orlov of Russia. He gave it to Catherine the Great.

The Hope Diamond (originally 122.5 carats, now 44.5 ) has a tradition of bringing bad luck to its owners. It was said to have been stolen from an Indian idol in 1642 by a Frenchman who later met a violent death. Louis XIV, the next owner, had the diamond cut down to 67 ¼ carats and called it the French Blue. The diamond disappeared during the French Revolution but was found again in London in 1830, cut to its present size. It was bought by Henry Thomas Hope, a banker. Later it appeared in Turkey, and in 1911 was bought by Edward McLean, an American. The diamond was given to the Smithsonian Institution in 1958.