Thursday, 23 November 2017

Citrine

Citrine is one of the most popular gemstones available today. It belongs to the very large family of quartz (SiO2) gemstones. It is the yellow to golden-orange variety of gemstone-quality macrocrystalline quartz (silicon dioxide).

The name 'citrine' was derived from 'citron', a French word meaning 'lemon'.
Natural citrine is rare and more valuable than most other varieties of quartz. Much of the citrine today is heat-treated to obtain its golden color. Almost all heated citrine will exhibit reddish tints.

Citrine is very closely related to violet-purple amethyst, another variety of macrocrystalline quartz. The only difference between citrine and amethyst is the oxidation level of iron ions (Fe3) present in colorless quartz crystal. When quartz is heated, iron impurities are reduced, resulting in less violet-purple color and more golden to orange colors.
Citrine is known to occur with excellent transparency. Eye-clean specimens are quite common leaving no reason to buy citrine stones with inclusions. Citrine has a vitreous luster when cut and polished.

Citrine is almost always faceted. Round brilliants and ovals are most common.

Tuesday, 21 November 2017

'Pink Promise' leads Christie's Hong Kong

'The Pink Promise' will be the top lot at Christie’s Hong Kong upcoming Magnificent Jewels sale. The 14.93 carat fancy vivid pink VVS1 diamond has a wide estimate of $28m to $42m.

The sale features 27 jewels by renowned jewelry artist Wallace Chan.

A 8.80 carat fancy intense pink diamond carries an estimate of $8.8m to $12m.
Top lot among rubies is an 8.17-carat pigeon’s blood Burmese ruby with an estimate of $5.8m to $8m. The supply of large Burmese ruby is dwindling, driving prices ever higher.

Burmese rubies of 4.04 and 4.03 carats. The pair has an estimate of $2m to $3.2m.
A 28.04-carat Sri-Lankan Padparadscha sapphire carries an estimate of $2m to $2.8m

A Jadeite bead and diamond necklace $7.3m to $10m. A jadeite pendant $3.5m to $4.8m

Monday, 20 November 2017

Yellow Diamonds to cross the Block at Bonhams

Five fancy vivid yellow diamonds with a historical connection to the Cullinan family will go under the hammer in London at Bonhams Fine Jewellery sale on December 7.

Three of the step-cut diamond are 5.29 carats, 3.11 carats and 2.37 carats and form a brooch carrying a high estimate around $400,000. The others are 2.08 carats and 1.93 carats and together are high estimated around $100,000.

Sunday, 19 November 2017

Green Diamonds


The 5.03 carat Fancy Vivid Green 'Aurora Green' made $16.8m or $3.3m per carat in 2016.
Green diamonds are among the rarest of all fancy colors. The green color is caused by exposure to radiation or radioactivity and is extremely unique.

Natural radiation creates an external skin or surface of green color. It is uncommon for the green color to reach deep within a diamond.
Lab graders assess the natural color of green diamonds by this skin. Irradiated green diamonds are often found in the marketplace, so determining natural color for value is key. Labs may be unable to conclusively determine the natural origin of green diamonds because the cause is radiation.

1.56 carat, Fancy Vivid Green Diamond
Green is the color between blue and yellow, so common secondary colors in green diamonds include bluish green and yellowish green, and if the color is desaturated, grayish green or brownish green. Natural green diamonds are second to red diamonds as the world's rarest fancy color. True greens devoid of secondary hue are the most valuable among natural green diamonds.

The green diamond has a very strong emotional correspondence with safety as it is the most restful color for the human eye. Green suggests both stability and endurance. Aqua green is associated with emotional healing and protection while Olive green is the traditional color of peace.
The Dresden Green is a 40.70 carat, pear shaped stone with a VS1 clarity grade. It was reported as one of the largest and finest natural green diamonds ever discovered.
The Ocean Dream The diamond is a 5.51-carat, fancy deep blue-green, shield-shaped diamond.

It is the only natural diamond known with this color combination.
The Chopard Chameleon, is a 31.31ct Oval-cut diamond which appears green in bright light but looks yellow in darkness. This stone was one of the first reported by the GIA as a chameleon in the late 1950s.

Cushion-shaped fancy intense green diamond weighing 6.13 carats, within a brilliant-cut pink diamond surround, extending to the half-hoop, mounted in 18k rose gold.

A square-shaped fancy green diamond weighing 10.36 carats, set in a ring within a pear-shaped and round cut pink diamond surround.

3.15 carat, Fancy Intense Yellowish Green diamond. VS1.
Fancy vivid green diamond weighing 2.52 carats. It made $ 3,106,500 CHF at Sotheby's in 2009.

Saturday, 18 November 2017

Elbaite Tourmaline

Elbaite is the most well-known and valuable form of tourmaline. Most multicolored tourmalines and almost all tourmaline gems are of the elbaite variety. Elbaite is perhaps the most multicolored mineral, coming in virtually every color of the spectrum. Originally discovered on the island of Elba, Italy in 1913, it has since been found in many parts of the world.

Elbaite contains many variety names based on color. A blue variety is indicolite, the pink to red variety is called rubellite, the green variety is known as verdelite. A pink and green combination is watermelon tourmaline.

Elbaite is one of the most varied minerals in terms of color. Colors include green, red, pink and blue. White, colorless, black, brown, yellow, orange, and purple colors are less common.

Crystals are frequently multicolored, containing two or more distinct colors. Some specimens are pleochroic.

Faceted Watermelon Tourmaline

Hearts and Arrows Diamonds

When it comes to diamonds, the hearts and arrows diamond is the masterpiece. What precisely is 'hearts and arrows'? When viewed from the top (crown), an ideally cut diamond should reveal eight symmetrical arrows. When the diamond is viewed from the bottom (pavilion), it should reveal eight symmetrical hearts. Not all diamonds with an ideal cut rating (AGS) or excellent cut rating (GIA) will automatically qualify as a hearts and arrows diamond. The formation of a precise patterning is due to extreme care that is taken when polishing each facet to exact angles and proportions. This level of precision goes far beyond the criteria needed to achieve a “excellent” symmetry rating.
There is a premium placed on super ideal cut diamonds, and while vendors can advertise their inventories with fanciful marketing, the details are essential.
The hearts patterning is particularly critical.

Properly formed hearts require super precise facet placements and proportioning. Any slight deviations in facet alignments will show up in the pavilion view.

Friday, 17 November 2017

Birds by Cartier

Cartier Bird of Paradise Brooch with 20.22-carat pink sapphire and six padparadscha sapphires.
Société Cartier designs, manufactures, distributes and sells jewellery and watches. Founded in Paris in 1847 by Louis-François Cartier, the company remained under family control until 1964.

Ruby, sapphire, emerald, citrine and diamond flamingo clip. Cartier 1940.

Cartier 1950s Emerald Ruby Sapphire Diamond Parrot Brooch
The company's headquarters is in Paris and it is now a wholly owned subsidiary of Compagnie Financière Richemont SA. Cartier has a long history of sales to royalty and celebrities.  King Edward VII of England referred to Cartier as "the jeweller of kings and the king of jewellers." Cartier operates more than 200 stores in 125 countries, with five flagship stores world-wide.

Morganite, Pearl, Onyx, Pink Sapphire and Mother of Pearl Bird Brooch