Saturday, 31 December 2016


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.

Friday, 30 December 2016

Orange Diamonds

The largest fancy-vivid orange diamond known to exist sold for 32.6 million Swiss francs ($36 million) at Christie’s International in Geneva in late 2013.

The 14.82-carat pear-shaped stone’s price was about $2.4 million per carat, this was a per-carat record for any colored diamond at a public sale. The gem also set a record for an orange diamond of its type.
Light Orange, Fancy, Fancy Intense Orange, Fancy Vivid Orange and Fancy Deep Orange
A 4.08-Carat Fancy Vivid Orange Diamond Ring blew past it's US$1.6 – 1.8 million estimate at Sotheby's Hong Kong auction in April 2016, bringing $ 2.3m

The 'Mandarin Orange' is a 4.19-Carat Fancy Vivid Orange Diamond. It sold for $2.9 million in 2011.

Orange Diamonds may contain a brown, yellow or pinkish modifying color.
The majority of diamonds contain some nitrogen. In orange diamonds the nitrogen atoms have grouped themselves in a very specific way. This happens during and right after the diamond is formed. Nitrogen arrangements absorb light in the blue and yellow region of the spectrum producing an orange color.
The strength of colour is one of the most important factors in determining the value of a natural color diamond. The value increases exponentially with the intensity of the most prominent colour within the diamond. Pure Orange diamonds are impossibly rare.
The Pumpkin Diamond is 5.54 carats and rated as Fancy Vivid Orange by the GIA. Halle Berry wore the ring to the 2002 Oscars where she won the Academy Award for Best Actress for her role in Monster's Ball. The popularity of orange diamonds zoomed.

2.00-carat, fancy vivid orange, heart-shaped Lady Orquidea Diamond
50.34 carat marquise-shaped Natural Fancy Deep Brown-Orange diamond. $ 1.1m.

Fancy Vivid Orange Yellow & Fancy Brown Orange Pink IF Pear Shape Diamond TW 10.62cts.

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

Wednesday, 28 December 2016

Colour Change Spinel

Spinel is a hard vitreous magnesium aluminum oxide that has been used as a gemstone for centuries. Spinel has been mistaken for ruby and sapphire in the past. Spinel occurs in a range of colors.
Spinel can be distinguished from other gemstones by its octahedral crystal structure and single refraction. Spinel has a lower Mohs hardness than ruby and sapphire. Spinel occurs with ruby and sapphire, and significant deposits have been found in Cambodia, Myanmar (Burma), Sri Lanka (Ceylon) and Thailand.

The rarest and most desirable spinel gemstones are vivid ruby-like red, followed by cobalt blue, bright pink and bright orange. Prices for 'class A' color-change spinel offer excellent value. According to some experts, current prices for color-change spinel are an insult to their beauty and extreme rarity.
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Tuesday, 27 December 2016

Top Diamonds of 2016

The Constellation, a 813-carat rough became the most valuable diamond of the year when it sold for $63.3 million in May. It was found at Lucara's Karowe mine in Botswana. It was bought by Nemesis International, which sold the rights to market the huge rough to Fawaz Gruosi of de GRISOGONO.

The day before the discovery of The Constellation, an even bigger diamond was found at Karowe. The 1,109 carat Lesedi La Rona – the second largest uncut diamond in history. Lucara plans to sell the stone in H1 2017.
Also in May, the Oppenheimer Blue, a 14.62-carat emerald cut Fancy Vivid blue diamond dubbed the “gem of gems’, sold for $57.7 million at Christie’s Geneva, setting a world auction record price for a blue diamond and becoming the most expensive gemstone ever sold at auction. $ 3.9m per carat. The 5.03 carat Fancy Vivid Green 'Aurora Green' made $ 16.8m or $3.3m per carat.

The 10.10-carat De Beers Millennium Jewel 4 sold for $32 million or $ 3.1m per carat in April of 2016.
The 15.38-carat Fancy Vivid Pink ‘Unique Pink’ became the most expensive Fancy Vivid Pink diamond ever to sell at auction in May 2016. It made $31.6m or $ 2.05m per carat.

A 7.32-carat pear-shaped fancy vivid blue diamond sold for more than $17.1 million at Sotheby’s Geneva in May. $ 2.3m per carat
The Sky Blue Diamond, an 8.01-carat fancy vivid blue diamond on a ring by Cartier, sold for more than $17 million in November. $ 2.1m per carat.

A 9.14 Carat pear-shaped, fancy vivid pink, VS2-clarity diamond sold for $18.2 million at Christie’s.

The 24.18-carat “Cullinan Dream,” brought $ 25m at Christie’s on June 9. $ 1.03m per carat.
Pair of diamonds, weighing 52.55 and 50.47 carats, D colour, IF Type IIa. They sold for $17.6 million at Christie’s Geneva in November.

17.07 carat fancy intense pink diamond VVS1 made $20.8m in November 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.