Saturday, 31 December 2016

Tanzanite

Tanzanite is the blue/purple variety of the mineral zoisite. It was discovered in the Mererani Hills of Manyara Region in Northern Tanzania in 1967, near the city of Arusha and Mount Kilimanjaro.

Naturally formed tanzanite is extremely rare. Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet and burgundy depending on crystal orientation.
Tanzanite is a relatively new gemstone in the world of gemology and jewelry. Since its discovery, tanzanite has sold for as little as $20 per carat and as much as $1,000 per carat or more, for gem-quality, finely coloured stones.
That price may seem like a bargain in time, as tanzanite is a one-source gemstone and that source is expected to be mined out within the next 15 to 25 years.
Pleochroic means tanzanite offers three distinct colors in three crystal directions. Tanzanite has a Mohs hardness of 6 to 7.

Thursday, 29 December 2016

Alrosa Rough and Polished Auction

Alrosa will hold a tender of polished and rough diamonds during Israel’s sixth International Diamond Week.

The auction will offer 108 boxes of rough diamonds of 11 to 199 carats, and several white and fancy color polished diamonds, weighing from 10 to 80 carats, including five that were cut from one large rough stone. The centerpiece of the Alrosa auction is the 80.59-carat round Star of Viluysk

Tuesday, 27 December 2016

Chrysoberyl - Alexandrite

Chrysoberyl is an aluminate of beryllium with the formula BeAl2O4. Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones. Chrysoberyl is the third-hardest frequently encountered natural gemstone.

The three main varieties are ordinary yellow-to-green chrysoberyl, cymophane (cat's eye), and alexandrite.
Cymophane exhibits chatoyancy or opalescence that appears very much like an eye of a cat. When cut to cabochon, the mineral forms a silky band of light extending across the surface of the stone.

Microscopic tubelike cavities or needlelike inclusions of rutile are orientated parallel to the c-axis producing the chatoyant effect.

Alexandrite undergoes dramatic shifts in color depending on what kind of light it's in. A variety of Chrysoberyl, alexandrite's color-changing properties is due to an exceedingly rare combination of minerals that includes titanium, iron and chromium. Originally discovered in Russia’s Ural Mountains in the 1830s, it’s now found in Sri Lanka, East Africa, and Brazil.
Fine, gem quality material is exceptionally rare and valuable. Alexandrite's mohs hardness is about 8.5.

Thursday, 22 December 2016

Spectacular Jewels

Van Cleef & Arpels “Lady Jour des Fleurs” Poetic Complication timepiece. The watch is crafted in 18-karat gold and set with an array of diamonds and gemstones. The watch is set with a total of 1,410 round diamonds weighing 15.40 carats. Additional gemstones include 173 yellow and pink sapphires weighing 2 carats, 161 tsavorite garnet weighting 2.50 carats, 106 Spessartite garnets weighing 1.60 carats and 54 Spinels at 0.4 carats for a grand total of more than 21 carats of stones.

Datura necklace, from Cartier’s Magicien Collection. Rubellite cabochon detachable drop with clusters of rubellite beads set among white and orange diamonds. HK$7.35 million
Cartier Magicien High Jewelry Panthère Asymétrique. The case and bracelet is set with 64 baguette-cut diamonds totaling 8.10 carats, 397 brilliant-cut yellow diamonds totaling 3.22 carats, 186 brilliant-cut orange diamonds totaling 0.83 carats, 315 brilliant-cut diamonds totaling 1.78 carats. In all nearly 1,000 diamonds and 14 carats.
Green tsavorites sparkle in a rose bracelet of Tiffany. Yellow Diamonds, white diamonds and spessartites.

Wednesday, 21 December 2016

Sotheby's Magnificent Jewels - New York

Sotheby’s sold $29.7 million worth of jewelry at two auctions in New York. A diamond ring from the collection of philanthropist Marjorie Fisher turned out to be the most expensive item. The marquise-shaped, 18.04-carat, D-color, VVS1-clarity diamond fetched $1.8 million, or $102,134 per carat This price surpassed a pre-sale estimate of $1.25 million to $1.75 million.

A 18.10-carat, D-color, VS1-clarity diamond ring found a buyer for $1.5 million, or $80,249 per carat. Separately, a cushion-cut, 10.19-carat, D-color, internally flawless diamond went for $1.3 million, or $130,765 per carat.
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The Magnificent Jewels sale that took place on Dec. 9 at Sotheby’s New York marks the last jewelry auction of 2015. The auction brought in $52.2 million.

The top lot was a 25.87 ct. sugarloaf cabochon Kashmir sapphire and diamond ring that sold for $5.1m, exceeding its high estimate of $4.5 million. A diamond necklace created by Van Cleef & Arpels in 1939 for Queen Nazli of Egypt made $4.3 million.



Pair of white gold, chalcedony, sapphire, and diamond cuff bracelets by Suzanne Belperron sold for $526,000

A platinum and diamond brooch by Bvlgari sold for $1.75 million, far exceeding its high estimate of $700,000.

A 38.27 ct. emerald-cut diamond ring sold for $4m

Tuesday, 20 December 2016

The Harrods Diamond

The Harrods Diamond is a 228.31 carat pear-shape stone graded G colour with VS1 clarity - a rare specimen and one of the largest diamonds of our times. A quality diamond of over 100 carats is impressive; over 200 carats puts the stone into another league.

It appears that the stone has been cut recently, suggesting that the diamond that emerged from Harrods was a rough. The size of the rough and its provenance is anyone’s guess. The largest white to recently come to auction is an 118 carat D colour Flawless diamond that broke records in Hong Kong in 2013 when it sold for $30.6 million.

Gem Butterflies

The incredible colours of rhodochrosite, haüyne, sphene, yogo sapphires, tanzanites, hiddenite, garnets and benitoites at the Los Angeles County Natural History Museum, in the Butterfly Broach Collection.

http://gringa-gem-news.blogspot.ca/2012_06_01_archive.html


This brooch is almost entirely set with benitoite, the California state gemstone.
A barium-titanium silicate mineral (BaTiSi3O9), benitoite is a rare mineral, crystals large enough to be cut into gemstones are found only in one location: the Dallas gem mine in San Benito County, California. An unusual geologic setting of hydrothermal veins between glaucophane schist and serpentinite created this rare mineral. Benitoite is known for its high dispersion and its vivid blue fluorescence in UV light.
Orange spessartine garnets from the Little Three mine in Ramona, California highlight this brooch, along with colorless diamonds and green tsavorite garnets from Kenya.
The multi-colored sparkle of this butterfly emanates from its green titanites (“sphene”) from Madagascar. The "fire" of titanite derives from its high dispersion and refraction. Titanite (CaTiSiO5) is a fairly common accessory mineral in igneous and metamorphic rocks, but is seldom found in size and quality suitable for gems.


This butterfly brooch brings together titanites in three different colors: green from Madagascar, brown and yellow from Pakistan.

A 13.51ct rhodocrosite (MnCO3). This mineral is very rare in jewelry. Apatite and opal cover the wings, the eyes are green chromium-rich titanite (sphene).
Pink and red spinels from Vietnam highlight this butterfly brooch. Red spinel (MgAl2O4) has long been used as an affordable alternative to ruby. Some famous historical rubies are actually red spinels. Spinel is now very popular in its own right. The eyes of the butterfly are blue jeremejevites (Al6(BO3)5(F,OH)3) from Namibia.
A 10.01-ct green hiddenite is the central piece of the brooch. Hiddenite is a green variety of the mineral spodumene (LiAl(SiO3)2) in which the color is caused by small amounts of the element. chromium. Hiddenite from North Carolina is found associated with emerald, the green variety of beryl, which also owes its color to chromium. The body of this butterfly is the world's largest faceted hiddenite.
This butterfly brooch is set with blue sapphires from Yogo Gulch, Montana. Sapphire senso stricto is the blue variety of corundum (Al2O3).

Wallace Chan

Eli Frei

Van Cleef & Arpels

Diamond and Gemstone Butterfly Brooch in 18K and Platinum.

Victorian Gemstone Butterfly Brooch

A pearl, diamond and cabochon emerald butterfly brooch by Buccellati.

A carved boulder opal butterfly brooch with diamonds and sapphires.

Cindy Chao

Fire Opal Butterfly brooch by Shaun Leane.

Anna Hu’s pair of high jewellery earrings.


Van Cleef & Arpels Papillons Butterfly blue and diamond brooch

Van Cleef & Arpels

Akiva Gil

Graff multi-cut diamond butterfly brooch 119.99 carats

Wallace Chans " Whimsical Blue" Butterfly