Two different shades of green are observed: a moss-like green, which is mainly seen in gems with a yellow or a brown tint; and a neon-like green, seen in gems with a blue tint. The existence of these shades can affect the price dramatically, positively or negatively.

In this article we decided to explore the price variations of green diamonds and understand the influence of each moderator on the green body color. For this purpose, we sought assistance from the GemePrice™’s back office. Its database includes more than $10.7 million worth of GIA-certified green colored diamonds currently available on the Internet, and is updated once every minute.

Through analysis of the available data, we compared the various color moderators of the green to a pure green diamond, which we set as our baseline of 100 percent.

The results of the analysis are shown in Figure 1. According to the database, the moss-like green colors had a negative effect on the price. Green colored diamonds with yellowish or yellow moderators were priced lower than the pure green by 20 percent and 40 percent respectively. Similar results are apparent with a brownish tint, where there was a 30 percent fall from the price of the pure green color stone.

On the other hand, the neon-like green colors add a premium to the price. A small addition of a bluish tint increases the price by approximately 20 percent. If the gem possesses an even higher blue saturation – high enough to be graded as a Blue Green color – the price jumps by about 50 percent.

The last tint we analyzed was gray. Although this is a neutral tint which cannot be attributed specifically to one of the two green shades, it induces its own effect, and it is quite negative. Simply stated, a gray-tinted moderator sliced the price in half.

The results point to a very clear price structure. While yellow, brown and gray tints tend to decrease the price of the gem, blue coloration causes it to increase sharply.

The neighbor’s diamond may be greener, but is it bluish or yellowish? That’s what really counts.

By Guy Borenstein, FGA

RAPAPORT… The Osenat auction house in Fontainebleau, France sold the engagement ring Napoleon Bonaparte gave Josephine de Beauharnais for approximately $1.2 million, including buyer’s premium, against a presale estimate of $13,000 to $20,000 (EUR 10,000 to EUR 15,000). 

The gold ring (pictured) garnered fierce and active bidding during the sale and features a pear-shaped sapphire and a diamond, set in the form of a toi et moi,  that reportedly weigh just under a carat each. The auction house defined the ring as part of a collection from the Emperor Napoleon III and Empress Eugenie.

Bonaparte gave the ring to de Beauharnais on February 24, 1796 from the collection of gems of the Imperial House. The couple married March 9, shortly before Bonaparte departed to carry out plans to invade Italy. Osenat held the sale on March 24 to mark de Beauharnais’ 250 birthday.

There are a few styles to choose from, below are a few of my favorites; all retail for $225.00 at cisthene.com

Malachite has been used ornamentally since the Early Dynastic period in Egypt. Carved into protective amulets and powdered for pigments in both paintings and eye cosmetics, the stone was honored among Egyptians and thought to be part of God’s physical realm. Several cultures have also linked Malachite to children – it was used as a teething stone and believed to keep evil from children and encourage a restful nights sleep. It is associated with the sign of Taurus.

Turquoise is one of the few stones to be worn by kings and common citizens alike. It still plays a vital role in the lives of traditional Navajo who rely on the stone stone’s healing and protective charms. The Apache believed that a medicine man was powerless without the stone and Middle Eastern and Tibetan cultures alike still honor Turquoise for both medicinal and ritual purposes. It the birthstone of December and linked to Sagittarius.

RAPAPORT… Sotheby’s New York annual spring auction of Magnificent Jewels on April 17 will offer 400 lots and a combined presale estimate in excess of $35 million. The centerpiece of this sale is an exceptional 74.79-carat, D, VVS1, potentially flawless, type IIa,  pear-shaped diamond with a presale estimate of $9 million to $12 million.

Lisa Hubbard, the chairman of North & South America at Sotheby’s International jewelry division, said,  “This truly exceptional stone exemplifies the strength of the white diamond market over the last decade. It was acquired by the present owner in 2001 for $4.3 million and today we have estimated it conservatively at $120,000 per carat. The stone has universal appeal and we anticipate that it will draw attention from both the diamond industry and discerning private  collectors alike.”

Hubbard added that the upcoming auction includes a number  of fresh-to-the-market pieces, such as rare colored stones from the Gould family and iconic styles including Cartier’s Tutti Frutti bracelet and panther brooch.

Highlights from the sale will be on view at the Hong Kong Convention & Exhibition Center from April 3 to 7 before returning to New York for exhibition on April 13, alongside a selection of pieces from the upcoming Geneva auction of Magnificent Jewels & Noble Jewels.

One of the highlights, a magnificent pair (5.79 carats and 5.68 carats) of pink diamond earclips,  was first sold Sotheby’s in 1987 and this lot returns with a presale esimtate of $3.5 million to $4.5 million. Sotheby’s stated that these earclips are distinguished by their classic pear-shaped diamond pendants,  an exquisite pair of pink diamonds that are particularly rare today as they were cut prior to the modified cuts being introduced to the market. Another highlight comes from the estate of Lynn Wolfson, a 21.46 carat, D, internally flawless, type IIa, emerald-cut diamond ring with a presale estimate of $2.5 million to $3.5 million.

Sotheby’s will also auction six jewels from the Gould family collection,  many pieces of  which were acquired in the first half of the 20th century, including a 22.48 carat emerald and diamond brooch, a 15.23 carat emerald and diamond ring and a 31.34 carat sapphire and diamond ring.

GIA recently examined a rare orange diamond that demonstrated the complexity of diamond color origin.   Diamonds with an orange bodycolor are usually caused by an absorption band centered at approximately 480 nm or by a high concentration of isolated nitrogen. Meanwhile, it is well known that the 550 nm absorption band often introduces pink to red colors.

Physical models of these two optical centers have not been resolved yet. The laboratory in New York recently examined an orange diamond whose color was attributed mainly to the 550 nm absorption band.   This 1.53 ct heart-shaped diamond (6.84 × 7.76 × 3.88 mm) was color graded as Fancy Intense pinkish orange. Color was distributed evenly throughout the stone, which was very clean and showed no internal features under the microscope.

The absorption spectrum in the infrared region revealed that it was a regular type IIa diamond, with no nitrogen- or hydrogen-related absorptions. In the UV-Vis region it showed a broad absorption band centered at approximately 550 nm and its corresponding band at about 390 nm, absorption features typical of natural type IIa pink diamonds.   From the optical centers detected, we would not expect this diamond to show a dominant orange bodycolor. The reason for this discrepancy is not fully understood.
– Wuyi Wang and Ren Lu GIA, New York

“The Impossible” nominee Naomi Watts wore 20-carat platinum and diamond drop earrings and a platinum and diamond bracelet ($1.5 million total) with her gunmetal sequined Armani. Charlize Theron’s vintage Harry Winston platinum and diamond bracelets totaled more than 100 carats added the right amount of luxe to her divine Christian Dior.

Although “Les Miserables” winner Anne Hathaway’s Prada dress didn’t show off her Tiffany & Co. diamond and platinum “Corsage” neckace to its best advantage, the $485,000 piece was still beautiful.

There were quite a few gorgeous gold pieces on the red carpet: “Zero Dark Thirty” star Jessica Chastain wore a vintage Harry Winston diamond and gold bracelet that coordinated with her bronze Armani gown, while Samantha Barks of “Les Miserables” used her low-cut Valentino to show off a House of Waris for Forevermark pendant in yellow gold with an oval Forevermark diamond. Best bracelet? “Skyfall”‘s Naomie Harris’ “Sunrise” bracelet in 18 karat gold with citrines and diamonds.

Garnet, January’s Birthstone

Garnet have been known to Man for thousands of years, its name may have derived from either the Middle English word Garnet meaning ‘dark red’, or the Latin word granatus (“grain”), which means something like ‘the grainy one’,

Garnets are wonderful deep-red gemstones and are also known for its many names;

• Almandine garnet, andradite garnet, demantoid garnet, grossularite garnet, hessonite garnet, pyrope garnet, rhodolite garnet, tsavorite garnet , spessartine garnet, and uvarovite garnet.

In early ages, garnets were exchanged as gifts between friends to show forth affections for each other and to insure meeting again.