Group of precious and semiprecious stones both uncut, faceted including (clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone or gem (also called a fine gem, jewel, precious or semi precious stone) is a piece of crystal (mineral), which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli) or organic materials that are not minerals (such as amber or jet), are also used for jewelry, and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone. Apart from jewelry, from earliest antiquity engraved gems and hard stone carvings, such as cups, were major luxury art forms. The carvings of Carl Faberge are significant works in this tradition.
Cutting and Polishing
A few gemstones are used as gems in the crystal or other form in which they are found. Most however, are cut and polished for usage as jewelry. The picture to the right is of a rural, commercial cutting operation in Thailand. This small factory cuts thousands of carats of sapphire annually. The two main classifications are stones cut as smooth, dome shaped stones called cabochons, and stones which are cut with a faceting machine by polishing small flat windows calledfacets at regular intervals at exact angles. Stones which are opaque such as opal, turquoise, variscite, etc. are commonly cut as cabochons. These gems are designed to show the stone’s color or surface properties as in opal and star sapphires. Grinding wheels and polishing agents are used to grind, shape and polish the smooth dome shape of the stones. Gems which are transparent are normally faceted, a method which shows the optical properties of the stone’s interior to its best advantage by maximizing reflected light which is perceived by the viewer as sparkle. There are many commonly used shapes for faceted stones. The facets must be cut at the proper angles, which varies depending on the optical properties of the gem. If the angles are too steep or too shallow, the light will pass through and not be reflected back toward the viewer. The faceting machine is used to hold the stone onto a flat lap for cutting and polishing the flat facets. Rarely, some cutters use special curved laps to cut and polish curved facets.
Nearly 300 variations of diamond color exhibited at the Aurora display at the Natural History Museum in London. The color of any material is due to the nature of light itself. Daylight, often called white light, is actually all of the colors of the spectrum combined. When light strikes a material, most of the light is absorbed while a smaller amount of a particular frequency or wavelength is reflected. The part that is reflected reaches the eye as the perceived color. A ruby appears red because it absorbs all the other colors of white light (green and blue), while reflecting the red. The same material can exhibit different colors. For example ruby and sapphire have the same chemical composition (both arecorundum) but exhibit different colors. Even the same gemstone can occur in many different colors: sapphires show different shades of blue and pink and fancy sapphires exhibit a whole range of other colors from yellow to orange-pink, the latter called Padparadscha sapphire. This difference in color is based on the atomic structure of the stone. Although the different stones formally have the same chemical composition, they are not exactly the same. Every now and then an atom is replaced by a completely different atom (and this could be as few as one in a million atoms). These so-called impurities are sufficient to absorb certain colors and leave the other colors unaffected. For example, beryl, which is colorless in its pure mineral form, becomes emerald with chromium impurities. If manganese is added instead of chromium, beryl becomes pinkmorganite. With iron, it becomes aquamarine.
Gemstones are often treated to enhance the color or clarity of the stone. Depending on the type and extent of treatment, they can affect the value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone.
1. Culinan: On January 25, 1905, at the Premier Mine in pretoria, South Africa, a 3, 106- carat diamond was discovered during a routine inspection by the mine’s superin-tendent. Weighing 1.33 pounds, and christened the “Cullinan,” it was the largest diamond ever found. Frederick wells was 18 feet below the earth’s surface when he spotted a flash of starlight embedded in the wall just about him. His discovery was presented that same afternoon to Sir Thomas Cullinan, who owned the mine. Cullinan then sold the diamond to the Transvaal provincial government, which presented the stone to britain’s king Edward VII as a birthday gift. Asscher Studied the stone for six months before attempting the cut. The Cullinan was later cut into nine large stones and about 100 smaller ones, valued at millions of dollars all told. The largest stone is called the “star of africal I,” or :cullinan I” and at 530 carate, it is the largest-cut fine-quality color less diamond. The second largest stone, the “Star of Africa II” or “Cullinan II,” is 377 carates. Both of these stones, as well as the “Cullinan III,” are on display in the tower of London with Britain’s other Crown Jewels; the Cuillinan I is mounted in the British Sovereign’s Royal Scepter, while the Cullinan II sits in the Imperial State Crown.
2. THE REGENT DIAMOND: The regent diamond gained its fame when Napoleon chose to decorate his battle sword with it: the stunning, mammoth diamond is 140.64 carats in size, with a very slight, blue cast. The diamond was said to be discovered at the Golconda mine in India, and spirited out secretly by a slave, who hid It within a cut on his leg. In 1792, at the Crown Jewels of France were stolen, and the Regent Diamond was among the missing gems. Napoleon retrieved the stone for his own use in 1801. Napoleon married twise, and his latter wife was an Archduchess of Austria: nshe went back to her home country after his husband’s death, and the Regent passed into Austrian ownership. In time, the stone returned to France, as the generous gift of the archduchess’ father. It now rests in the louver, with many other spectacular gems.
3. THE SHAH DIAMOND: This diamond was discovered in India around 1450, and it has become a potent symbol of the royalty, war, and history of India from the sixteenth and seventeenth centuries. This diamond weight 88.7 carats, and it is Known for it’s crystalline clarity. The yellow diamond was seized, lost, and reclaimed by three different shahs during ancient time. And it retains the inscriptions that they left there overtime. One shah, Jehan, chose a telling description of himself to be engraved upon the diamond: “ruler of the world”. However, he too eventually loss the diamond as it was once again seized by another shah. After the murder of a Russian Member of the diplomatic corps in 1829, the reigning shah offered the diamond to the Kremlin, as a way of pacifying them and ensuring no violent retribution towards him by the soviet Union. In the manner, the ownership of the Shah diamond was lost to India forever.
4. DARYA-YE NOOR: The Darya-ye Noor which means “Sea of Light”, or “Ocean of light” in Persian; also spelled Darya-i-Noor, Darya-e Noor and Darya-i-Nur is on of the largest diamonds in the world, weighing an estimated 182 carats(36 g). its color, pale pink, is one of the retest to be found in diamonds. The Darya-ye Noor presently forms part of the lranian Crawn Jewels and is on display at the Central Bank of Iran in Tehran.
5. THE ALLNATT DIAMOND: The allnatt diamond is a diamond with the size of 101.29 carat (20.258 g) with a cushion cut. Rated in color as Fancy Vivid Yellow by the Gemological Institute of America. This diamond is named after one of the holders, Major Alfred Ernest Allnatt, a soldier, sportsman, art parton and supporter. Althought not known exactly where allnatt get this diamond, but many experts believe that it my be found in what is now known as the De Beers Premier Diamond Mine. Allnatt origins are not known before the purchase of diamonds by Major allnatt in early 1950s. after buying this diamond, he commissioned Cartier to make arrangements for the final setting to from a platinum flower with five petals, tow stems and leaver, all arranged by diamond. The allnatt was resold at an auction in May 1996 by Christei’s in Geneva for $3,043,496 US. At the time of sale allnatt is 102.07 carte (20.41 g). and assessed Fancy Intense Yellow. After the sale to Siba Corparation, a diamond is cut into the heavy again today and the intensity Increased as a result.
6. DE BEERS DIAMOND: In March 1888, the enormous, light yellow octahedron was found in the De Beers min The stone is often confused with a larger whit diamond called the imperial, Great White, or Victoria, howere mathematical calculations have shown otherwise.
7. MILLENNIUM STAT: In 1999, De Beers unveiled the De Beers Millennium Jewels – the centerpiece being the De Beers Millennium Star, a ‘D’ colour, flawless pear-shaped stone weighing 203.04 carats. The rast of the Millennium Jewels were made up of eleven rate blue diamonds with a total weight of 188 carats. The largest was the Heart of Etermity weighing 27.64 carats. The Millennium Star weighed 777 carats in the rough, and is the sixth largest diamond of gem quality ever discovered. It took the Steinmetz Group three years to cut the millennium Star. First of all it was split in Belgium, then polished in South Africa and subsequently finished in New York. In the end the diamond was shaped into a classic pear, with 54 facets.
8. THE MOUSSAIEFF RED DIAMOND: The moussaieff red is displayed as port of the Smithsonian’s “The Splendor of Diamonds” exhibition, in addition to the De Beers millennium Star and The Heart of Eternity. Moussaieff Red is reported to have been discovered by a Brazilian farmer in Abaetezinho river in 1990, in an area known as alto Paranaiba who had a reputation as a great sourece of beautiful and colorful diamond. Roughly. It was believed to be 13.9 carates(2.78 g). Diamond was purchased and cut by the Willian Goldberg Diamond Corp. and named the Red Shield. It is currently owned by moussaieff Jewelers Ltd. Moussaieff Red Diamond is a diamond the size of 5.1 carat(1. 022 g) by butting a triangular brilliant (sometimes called trilliant trillion or cut), given a color as Fancy Red by the. Althought this may seem relatively small when compared to other famous diamonds, the Moussaeff Red is, in fact, the largest Fancy Red.
9. THE VICTORIA-TRANSVAAL: The vicotira-transvaal is a 67.89-carat, champagne-color, pear shaped stone. It was cut from a 240-carat crystal that was found in the Transvaal, south Africa. The necklace was designed by Baum gold Brothers, Inc, and consists of a yellow gold chain with 66 round brilliant-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 necklace was donated by Leonard and Victoria Wilkinson in 1977 to the Smithsonian Institute, Washington D.C
10. EUREKA : The Eureka Diamond is perhaps the single most important diamond in the history of South African miming. Discovered in 1866 by children digging amongst the shrubbery of their father’s land, it remained for some time “undiscovered” – a mere playing for the children of Dutch farmer Daniel Johannes Jacobs. No one in the farmer’s home took it to be anything more than an attractive rack. In 1867 Atherton confirmed the “first” diamond to be discovered in South Aftica, stating it was a “veritable diamond weighing 24 carats.
11. KOH-I-NOOR: The koh-i-noor came into hands of numerous rulers they are porus, the king of Punjab Chandragupta maurya(325-297 B. C, Ashoka who ruled from 273-233 B.C., Raja Samprati of Ujjain (Ashoka’s grandson). Ujjain and the par mar dynasty of malwa, Rai Ladhar Deo, the ruler of Malwa, Ala-ud-din Khilji(1296-1316A.D.), Kughal Empero Babur, Humayun, Sher shah Tehmasp of Iran. The Shah sent the Koh-i-noor along with other precious gifts to burhan n izam shah of ahmednagar (Deccan) of the rulers of the Deccan – Ahmednagar, Golkunda and Bijapur regarded the King of Persia as their religious head. The stone remained in the possession of the Nizam shahi dynasty of ahmednagar and the Qutb Shah Rangila(1719 – 1748), Nadir Shah, Shah Shuja who handed it to Maharaja Ranjit Singh in 1813. The Koh-i-Noor left the shores of India on April 6, 1850, and on reahing London on July 2, 1850, it was handed over to the Board of Directors of the East India Company. Sir J.W. Logg, the Deputy Chairman of the East India Company, presented it to Queen Victoria.
12. CENTENARY: The centenary celebrations of De Beers took place in 1988 in Kimberley, in front of a captive audience of four hundred people. These included government representatives of producer countries and other important dignitaries from the diamond industry. Julian Ogilvie Thompson, the them Chairman, revealed that a diamond of 599 carats had been recovered from the premier mine.
13. Kimberley Diamond Mine South Africa: The Kimberley Diamond Mine (also Known as the Big Hole) holds the (disputed ) title of being the largest hand – dug hole in the world. From 1866 to 19614 50,000 miners dug the hole with picks and shovels, yielding 2,722 kg of diamonds. Attempts are being made to have it registered as a world heritage site.
15. Mirny Diamond Mine Siberia: The mirny diamond mine is 525m deeo and gas a diameter of 1200m. It was the first, and one of the largest, diamond pipes in the USSR. It is now abandoned. While it was still operational, it would take two hours for trucks to drive from the top to the bottom of the mine.
16. Golden Jubilee : Discovered in the Premier mine in South Africa in 1986, the 755.50 carat rough diamond was a beautiful golden yellow color with a bright reddish hue at the centre An underground room that was free from vibration had to be constructed before work could begin on the diamond. In 1990 after tow years of work, the stone was finished, reduced in total from 755.50 carats, to 545.65 carats. The diamond was named the Golden Jubilee, the diamond to be given to King Bhumibol as a gift from the people to celebrate the 50th anniversary of the King’s ascent to the Throne. The diamond is now on display in the Royal Museum at Pimammek Golden Temple Throne Hall in Bangkok.
17. Agra: It has been suggested that in 1526 the Agra Diamond was taken into the Possession of Babur, the first Mogul Emperor, after he defeated the Rajah of Gwalior in battle. It is recorded that Babur wore the Agra diamond in his turban. The agra was certified as a fancy has again been re cut, to 28.15 carats.
We are giving original gem stone certificate