Showing posts with label aquamarine. Show all posts
Showing posts with label aquamarine. Show all posts

Sunday, May 16, 2010

Jewels Shine at Auction

source : nytimes.com
"Gems and jewels have been doing brilliantly at auction for months, as if bidders had never been told that there is a recession," Souren Melikian writes.A late 18th-century pair of ear clips with spinels and diamonds, cataloged as "the property of a German Princely and Liechtenstein Ruling Family," almost quadrupled the high estimate at $105,000 at Sotheby's Geneva auction.On Dec. 10, when the mood in London was at an all-time low, Christie's sold the most expensive jewel ever. The 35.56-carat blue diamond rose to $24.31 million, or to be strictly accurate, £16.39 million, to Laurence Graff of London.The gem's history goes back to the 17th century, when Philip IV of Spain gave it to his daughter Margaret Theresa on her betrothal to Leopold I, the ruler of the "Roman Germanic Empire." Later, it belonged to the Princes of Wittelsbach in Bavaria. The stone was cut by Sa'ida-ye Gilani, the Iranian poet, calligrapher and jeweler employed at the Moghul court by the emperor Jahangir (who reigned from 1605-1627), thus multiplying its potential value manyfold. However, the catalog did not mention this, since it was not known at the time of the sale.Five months later, another extraordinary price within its range was realized at Sotheby's in Geneva. A fancy blue diamond, a 7.03-carat gem, brought in $9.48 million, just over $1.34 million a carat, making the diamond the most expensive stone per carat ever sold in any category.Where aristocratic provenance could be established, jewels soared sky-high. A diadem and necklace made by Cartier in 1912 for Olga Princess Paley, Countess of Hohenfelsen, both doubled their high estimates. The diadem (described as an "aigrette tiara") set with rose-cut diamonds and two aquamarines, brought $512,014.The necklace, designed in the same heavily ornate style, cost an equally breathtaking $392,700.
At Christie's late spring London sale of jewelry on June 10, signed jewels set with good quality stones sold like hot cakes regardless of style or period.

A necklace made from oval gold links joined by diamond-set clasps and signed Cartier Paris excited bidders, who sent it climbing to $42,750, more than triple the estimate.
Christie's "superb antique diamond brooch" was an unusual composite piece. Made up from magnificent 18th-century pear-shaped diamond drops hanging from an inverted lotus chalice, it exceeded the high estimate as a private collector from Britain footed the $374,824 bill.
In its own modest line, an Art Deco travel clock of spinach-green jade, its dial framed by a gold chain motif set off by black enamel, provided evidence of the private buyers' sunny disposition, as it brought $14,260, substantially more than the high estimate.

source : nytimes.com

Friday, January 4, 2008

Aquamarine - Jewelry photos

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Aquamarine on Quartz

Aquamarine on Quartz

Aquamarine - as a mineral


Aquamarine
Aquamarine
Aquamarine
General
Category beryl variety
Chemical formula Be3Al2Si6O18[1]
Identification
Color transparent (or can be translucent if included), greenish blue to blue green, typically light in tone[1]
Crystal system hexagonal[1]
Cleavage very difficult in one direction, almost never seen[1]
Fracture conchoidal[1]
Mohs Scale hardness 7.5 - 8[1]
Luster vitreous to resinous[1]
Polish luster vitreous [1]
Refractive index 1.577 - 1.583 (+/- .017)[1]
Optical Properties Double refractive, uniaxial negative[1]
Birefringence .005 - .009[1]
Dispersion .014[1]
Pleochroism weak to moderate, blue and greenish blue; or different tones of blue with lighter tones associated with the optic axis direction [1]
Ultraviolet fluorescence inert[1]
Absorption spectra indistinct lines at 537 and 456nm. Depending on the depth of color, there is a strong line at 427nm.[1]
Specific gravity 2.72 (+.18, -.05)[1]
Aquamarine (Lat. aqua marinā, "water of the sea") is a gemstone-quality transparent variety of beryl, having a delicate blue or turquoise color, suggestive of the tint of seawater. It's closely related to the gem emerald. Colors vary and yellow beryl (heliodor), rose pink beryl (morganite), and white beryl (goshenite) are known.

Composition

Aquamarine is a beryl with a hexagonal crystal structure and a chemical formula of Be3Al2Si6O18, a beryllium aluminium silicate mineral. It has a specific gravity of 2.68 to 2.74 and a Mohs hardness of from 7.5 to 8. Aquamarine typically is on the low end of the specific gravity range, normally at less than 2.7. The pink variety exhibits a high specific gravity of around 2.8. Refractive indices range around 1.57 to 1.58.

Locations of deposits

It occurs at most localities which yield ordinary beryl, some of the finest coming from Russia. The gem-gravel placer deposits of Sri Lanka contain aquamarine. Clear yellow beryl, such as occurs in Brazil, is sometimes called aquamarine chrysolite. When corundum presents the bluish tint of typical aquamarine, it is often termed Oriental aquamarine.

In the United States, aquamarines can be found at the summit of Mt. Antero in the Sawatch Range in central Colorado. In Brazil, there are mines in the states of Minas Gerais, Espírito Santo and Bahia. Zambia also produces nice aquamarine as well as Madagascar, Malawi, Tanzania and Kenya. Much of today's aquamarine is heated to give it a better color blue. The deeper the blue color, the more valuable the gem is considered.

The biggest aquamarine ever mined was found at the city of Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm long and 42 cm in diameter.

Aquamarine is the official state gem of Colorado.

Culture and historical/mythical usage

  • Aquamarine (along with Bloodstone) is the birthstone associated with March. It is also the gemstone for the 19th Anniversary.
  • People in the Middle Ages thought that aquamarine could magically overcome the effects of poison.
  • Ancient sailors traveled with aquamarine crystals, believing that it would ensure a safe passage, and guarantee a safe return; they often slept with the stones under their pillow to ensure sound sleep. They believed the siren’s (mermaid) fish-like lower body was made of aquamarine.

source : http://en.wikipedia.org/wiki/Aquamarine