Tuesday, 30 April 2019

Van Cleef and Arpels - Seven Seas

Venerable Parisian high jewellery house Van Cleef & Arpels took to the sea in 2015 with its 'Seven Seas' resort collection.


Christie’s to Sell Historic Golconda Diamonds

Christie’s New York auction will feature a 17.21-carat diamond given to Queen Charlotte of Great Britain by a regional ruler in India. The pear-shaped, brilliant-cut diamond, called Arcot II, was found in India’s Golconda region in the late 18th century. The stone, presented to the queen by the Nawab of Arcot, will go under the hammer at the Maharajas & Mughal Magnificence sale on June 19.

Christie’s will also offer the Mirror of Paradise, a 52.58-carat, D-color, internally flawless Golconda diamond, as well as carved Mughal emeralds ranging from approximately 10 carats to over 200 carats.

Monday, 29 April 2019

Black Argillite


Argillite Eagle box by Haida artist Bill Reid
Argillite is a fine-grained sedimentary rock composed predominantly of indurated clay particles. Argillaceous rocks are lithified muds and oozes.

The Haida carvings of Haida Gwaii (formerly the Queen Charlotte Islands) along the coast of British Columbia are famed aboriginal art treasures created from a type of a hard, fine black silt argillite.
Black argillite occurs in only one place in the world, at a quarry on Slatechuck Mountain near the town of Skidegate on Graham Island.

Graham Island is the largest island in the Haida Gwaii archipelago.

Argillite Otter Bowl by Lionel Samuels
There is one distinct difference in Haida Art compared to other West Coast native art cultures, Argillite. Black Argillite is only found on Haida Gwaii and is carved by many Haida artists.

Sunday, 28 April 2019

Kyanite

Kyanite is composed of aluminum silicate; the same as andalusite and sillimanite. Kyanite has a different crystal structure (triclinic) and thus exhibits different physical properties. One of the unusual properties of kyanite is that it has a variable hardness - it is soft when cut parallel to the long axis of the crystal, with a hardness of only 4 to 4.5 on the Mohs scale. It's hardness is about 6.5 when cut perpendicular to the long axis. Kyanite has a vitreous to pearly luster. Generally kyanite gems are not found in large sizes
Blue kyanite has long been used as a sapphire imitation. Bright blue kyanite from Nepal might be mistaken for sapphire, but they are easily identified by their different inclusions and optical values. Recent finds of very high quality kyanite in Nepal are changing perceptions of this gem.

Daha is in Jajarkot District in the Bheri Zone of Mid-Western Nepal. Four small-scale kyanite mines are currently in operation in Daha and Suneri in Jajarkot, and Barah in Aachham District. Production is very limited.
High quality inky blue kyanite crystals are cut for gems.
Until recently, it was believed that kyanite always formed in shades of blue.

Orange kyanite has now been discovered in Tanzania. The orange color is derived from trace amounts of manganese in the crystals. Kyanite’s name does reflect the more common blue color, and is derived from the Greek word kuanos, which translates to “deep blue.”

Saturday, 27 April 2019

GIA features Yogo Gulch Sapphires

Nearly all of the rough crystals are flat, tabular pieces that can only be cut into small gems. Carat-plus sapphires are rare.The US has never been known as a major source for gemstones. The one exception has been Montana sapphire. Montana has been an important source of blue sapphire off and on since the 1890s. Yogo sapphires feature an attractive violet to blue color. They are not heat treated – the gem-quality stones rarely respond to treatments.
Yogo sapphires have a distinct trace element signatures with specific values of manganese, chromium, titanium, iron and gallium that are different from other sapphires. While Yogo sapphires command premium prices, their small sizes and difficult deposits make mining uneconomic.

In 1910 the largest sapphire ever found was revealed, a 19 carat rough that was cut into four gems, the largest 8.5 carats.
See ----->Yogo Gulch

Friday, 26 April 2019

Spinel from Omi Privé

Spinel has long been one of the most under-appreciated gemstones, yet it is coveted by collectors and gemologists for its range of hues and spectacular optical properties. While all colors of spinel are beautiful in their own way, red is the rarest and the most valuable.

Thursday, 25 April 2019

Champagne Diamonds

Beauty is a powerful thing - almost as powerful as semantics. There's no better evidence for this than the surging popularity of champagne diamonds - colored diamonds that in actuality, are brown diamonds with a luxe name and a yellowish shade.

As alluring and sought after as champagne diamonds are today, they weren't always so appreciated. In the past, natural fancy brown diamonds weren't especially trendy.
Champagne diamonds have managed to gain increasing attention in recent years from collectors and investors.

When Rio Tinto's Argyle Mine determined that nearly half of the stones in their deposit were brown, it was clear that new marketing tactics were required. They coined the term "champagne diamonds," which suggested an air of luxury, elegance and affluence. The word "champagne" is not used on grading reports from the GIA.
The color would be described as fancy light yellow brown, fancy yellowish brown, or similar. The Argyle Mine has devised a different color scale specifically to grade champagne diamonds, which ranges from C1 to C7. C1 to C2 are a light champagne, C3 to C4 are medium champagne, C5 to C6 are dark champagne, and C7 is considered "cognac.'
A major reason that champagne diamonds have been gaining vogue is that they have been embraced by the A-list celebrities. Color and its strength of hue is the most significant factor in determining value. The darker and rare cognac diamonds come at the highest cost, while champagne diamonds on the lighter end of the spectrum (C1 to C3) are more common and therefore less expensive.
The most well-known champagne diamond is the Golden Jubilee. It weighed 755 carats rough and resulted in a 545.67 carat gemstone. It's the largest faceted diamond in the world. Discovered in South Africa's Cullinan Diamond Mine in 1985, it was given to the King of Thailand in 1997 to celebrate his reign.

The Great Chrysanthemum Diamond is a fancy brown pear shaped modified brilliant cut of 104.15 carats. The diamond originated in South Africa.