Peridot (pronounced /ˈpɛrɪdɒt/ or /ˈpɛrɪdoʊ/) is gem-quality forsteritic olivine. The chemical composition of peridot is (Mg, Fe)2SiO4, with Mg in greater quantities than Fe.
The origin of the name "peridot" is uncertain. The Oxford English Dictionary suggests an alteration of Anglo-Norman pedoretés (classical Latin paederot-), a kind of opal, rather than the Arabic word faridat, meaning "gem".
Olivine in general is a very abundant mineral, but gem quality peridot is rather rare.
Peridot is one of the few gemstones that occur in only one color: basically an olive green. The intensity and tint of the green however depends on how much iron is contained in the crystal structure, so the color of individual peridot gems can vary from yellow-green through olive green to brownish green. The most valuable is considered a dark-olive green color.
Peridot crystals have been collected from some Pallasite meteorites. A famous Pallasite was offered for auction in April 2008 with a requested price of close to $ 3 million at Bonhams, but remained unsold. Peridot is the only gemstone found in meteorites.
Peridot olivine is the birthstone for August. It is sometimes mistaken for emeralds and other green gems. In fact notable gemologist George Frederick Kunz discussed the confusion between emeralds and peridots in many church treasures, notably the "Three Magi" treasure in the Dom of Cologne, Germany.
The most common colour of aventurine is green, but it may also be orange, brown, yellow, blue, or gray. Chrome-bearing fuchsite (a variety of muscovite mica) is the classic inclusion, and gives a silvery green or blue sheen. Oranges and browns are attributed to hematite or goethite. Because aventurine is a rock, its physical properties vary: its specific gravity may lie between 2.64-2.69 and its hardness is somewhat lower than single-crystal quartz at around 6.5.
Aventurine feldspar or sunstone can be confused with orange and red aventurine quartzite, although the former is generally of a higher transparency. Aventurine is often banded and an overabundance of fuchsite may render it opaque, in which case it may be mistaken for malachite at first glance.
The name aventurine derives from the Italian "a ventura" meaning "by chance". This is an allusion to the lucky discovery of aventurine glass or goldstone at some point in the 18th century. Although it was known first, goldstone is now a common imitation of aventurine and sunstone. Goldstone is distinguished visually from the latter two minerals by its coarse flecks of copper, dispersed within the glass in an unnaturally uniform manner. It is usually a golden brown, but may also be found in blue or green.
The majority of green and blue-green aventurine originates in India (particularly in the vicinity of Mysore and Madras) where it is employed by prolific artisans. Creamy white, gray and orange material is found in Chile, Spain and Russia. Most material is carved into beads and figurines with only the finer examples fashioned into cabochons, later being set into jewellery.
Main markets for aventurine are landscape stone, building stone, aquaria, monuments, and jewellery.
The Star of India is a 563.35 carat (112.67 g) star sapphire, probably the largest such gem in the world. It is almost flawless and unusual in that it has stars on both sides of the stone. The greyish blue gem was mined in Sri Lanka and is now kept in the American Museum of Natural History in New York City.
The milky quality of the stone is caused by the traces of the mineral rutile, which is also responsible for the star effect, known as the effect of asterism. The tiny fibers of the mineral, aligned in a three-fold pattern within the gem, reflect incoming light into the star pattern.
History
In 1900, wealthy financier J.P. Morgan donated the Star of India to the American Museum of Natural History on Central Park West in Manhattan. On October 29, 1964, the famous golf-ball-sized stone was stolen, along with several other stones, including the Eagle Diamond and the de Long Ruby. The thieves unlocked a bathroom window during museum open hours, climbed in that night, and found that the sapphire was the only gem in the collection protected by an alarm — and the battery for that was dead. So they raked up the stones and fled the same way they came in. The stones were valued at more than $400,000. Within two days, the notorious cat burglar, smuggler, and one-time surfing champion, Jack Murphy (also known as Murph the Surf), was arrested along with two accomplices, later receiving a three-year sentence. Some months later, the uninsured Star of India was recovered in a locker in a Miami bus station. While most of the other gems were also found, the Eagle Diamond was never seen again.
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The Star of the South, also known as Estrela do Sul, is a diamond found in Brazil in 1853. The diamond is cut into a cushion shape and weighs 128.48 carats (25.70 g). The Star of the South is graded as a type IIa diamond, with a colour grading of light pinkish-brown and a clarity of VS2. At the time of discovery, the diamond weighed 254.5 carats (50.9 g). It has passed through the hands of many owners, and its last known purchase was by Cartier store, when it was sold by Rustomjee Jamsetjee of Mumbai. The light reflected by the diamond is white, and the refracted light is of a rose tint. This gives the diamond its light pinkish-brown hue.
The diamond was found by a slave girl in 1853, at the Bagagem Diamond Mines in Brazil. It was handed over to her master, Casimiro de Tal, who rewarded her for finding the diamond by granting her freedom and a pension for life. Casimiro de Tal later sold it for £3,000, a price far lower than its actual value. The buyer deposited the diamond at the Bank of Rio de Janeiro for £30,000.
The uncut diamond was passed through the hands of several buyers, until it was bought by Coster’s Establishment of Amsterdam for £35,000. It was then cut into an oval cushion shape by a cutter called Voorsanger of Coster’s Establishment, at a cost of £500.
It was purchased by Halphen and Associates of Paris, a syndicate of diamond merchants led by Messrs. Halphen, who named it Estrela do Sul, or Star of the South. The syndicate exhibited the diamond 1862 at the London Exhibition, and again 1867 at the Paris Exhibition. On both occasions, the Star of the South received considerable attention. The diamond was later sent to a diamond dealing house in India, where negotiations were carried out to sell it to a Maharajah for a price of £110,000. However, this deal was not successful and the diamond was returned to Halphen and Associates.
During the diamond’s stay in India, Prince Mulhar Rao of the royal family of Gaekwad got to know about the stone. He instructed E. H. Dresden of London to purchase the diamond, who purchased it from Halphen and Associates for £80,000 on behalf of the prince. The Star of the South was in the possession of the Gaekwad family for several years. It was later mounted on a necklace along with the 78.5 carats (15.7 g) English Dresden diamond. In 1934, Prince Mulhar Rao’s son had told Robert M. Shipley, an American gemologist about this. In 1948, the Maharani Sita Devi of Baroda, was photographed wearing the necklace at her husband Maharajah Pratapsinh's birthday party.
The Star of the South was later purchased by Rustomjee Jamsetjee of Mumbai, who sold it to Cartier in 2002.
The Florentine Diamond is a lost diamond of Indian origin. It is light yellow in colour with very slight green overtones. It is cut in the form of an irregular (although very intricate) nine-sided 126-facet double rose cut, with a weight of 137.27 carats (27.454 g). The stone is also known as the Tuscan, the Tuscany Diamond, the Grand Duke of Tuscany, the Austrian Diamond and the Austrian Yellow Diamond.
The stone's origins are disputed. Reportedly, it has been cut by Lodewyk van Berken for Charles the Bold, Duke of Burgundy. Charles is said to have been wearing it when he fell in the Battle of Morat on June 22, 1476. A peasant or foot soldier found it on the Duke's person and sold it for a florin, thinking it was glass. The new owner Bartholomew May, a citizen of Berne, sold it to the Genoese, who sold it in turn to Ludovico Sforza. By way of the Fuggers it came into the Medici treasury at Florence. Pope Julius II is also named as one of its owners.
Another version of the stone's early history is that the rough stone was acquired in the late 1500s from the King of Vijayanagar in southern India by the Portuguese Governor of Goa, Ludovico Castro, Count of Montesanto, after the king's defeat by Portuguese troops. The crystal was deposited with the Jesuits in Rome until, after lengthy negotiations, Ferdinando I de' Medici, Grand Duke of Tuscany succeeded in buying it from the Castro-Noronha family for 35,000 Portuguese scudi crocati.
Duke Ferdinand's son, Cosimo II, finally entrusted his father's purchase to a cutter, Pompeo Studentoli, a Venetian working in Florence. The finished gem was delivered on October 10, 1615. An inventory drawn up on Cosimo's death confirms the acquisition of the rough diamond by Ferdinand and describes the gem as 'faceted on both sides and encircled by a diamond encrusted band'.
Documented history begins when Jean Baptiste Tavernier, the French jeweller and traveller saw the stone among the possessions of Ferdinando II de' Medici, Grand Duke of Tuscany in 1657. It then passed into the hands of the Habsburgs when the last of the Medicis died through the marriage of Francis III Stephan of Lorraine to Empress Maria Theresa of Austria and was placed in the Habsburg Crown Jewels in the Hofburg in Vienna. At the time it was valued at $750,000.
After the fall of the Austrian Empire during World War I, the stone was taken by the Imperial Family into exile in Switzerland. The stone was stolen some time after 1918 by a person close to the family and taken to South America with other gems of the Crown Jewels. After this, it was rumoured that the diamond was brought into the United States in the 1920's and was recut and sold.
The Noor-ol-Ain is the principle diamond mounted in a tiara of the same name made for Iranian Empress Farah Pahlavi's wedding to Shah Mohammad Reza Pahlavi in 1958. The Diamond is believed to have been recovered from the Golconda mines in India and was brought into the Iranian Imperial collection after the conquest of that country by Nader Shah Afshar in the 18th century.
It is one of the largest pink diamonds in the world and is believed to have once formed part of an even larger gem. That larger diamond is thought to have been cut in two, with one section becoming the Noor-ol-Ain and the other the Darya-ye Noor diamond. Both of these pieces are currently part of the Iranian Crown Jewels.
Noor-ol-Ain translated from Persian means the light of the eye.