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Year 3 Issue 12-- January 2005
ICA Gemstone Gallery
Exhibit at GIA New York
Fine jewellerySparles at Bonham's London
Auction
GIA on Diamond Cut
         
 
      The ICA GemBureau has scanned its vast collection of colored gemstone varieties, most of which are held on 35-milimeter slides. This unique collection is the hidden treasure of the International Colored Gemstone Association.
      The Collection consists of hundreds of high-quality photographs of colored gemstones. The project was started in the mid 1980s by Cheryl Kremkow, the first GemBureau director and the first editor of the ICA gazette.
      Bart Curren of Vancouver, Washington was the photographer for most of the slides. He is a gem carver and cutter in his own right. Bart would tour the booths of ICA members exhibiting at the gem shows in the US, and would then choose a variety of cut stones to photograph.
 
 
Fire Opal - Maxico -- ICA/Bart Current
  
 
Sapphire - Sri Lanka -- ICA/Bart Curren.
  
     
 
      These would often be often special samples as well as stones from new locations or a newly discovered gemstone species. Various trade journalists have also donated photographs that they have taken.

      This information was provided courtesy of the Gem Bureau, the promotional arm of the International Colored Gem-stone Association (ICA). ICA is the world's single international umbrella organization that represents the interests of colored gemstone miners, manufacturers (i.e. cutters and polishers), and wholesale distributors.
 
 
   
 
Spessarite - Nigeria - ICA/Bart Curren.
Garnet.
Jadeite - Burma - ICA.
Sphalerite.

This 69.88 cy. natural yellow-green Ukranian beryl
was donated to GIA by Michael Dyber, who also
cut the unique gem using his signature lapidary
technique "Dyber Optic Dish. "It is now on display
at the New York campas. Gift of Michael McCue Dyber.
    A unique exhibit of nearly 100 jewelry items, mineral specimens, gems, objets d'art, and carvings is now on display at the Gemological Institute of America's (GIA) New York campus. Originating from GIA's Museum Collection, the pieces represent some of the newer, exceptional additions to the Institute's set. It will be on display at GIA New York through 2005.
    On view throughout the New York campus, the exhibit aims to educate students and the public about the world of gemology. A single crystal of heliodor measuring 18 x 5.5 x 4.5 cm is one of the pieces featured. A variety of beryl, the stunning crystal is doubly terminated and shows interesting surface etching characteristic of the heliodors from the Wolodarsk pegmatites from the Ukraine, said GIA Museum Curator Terri Ottaway.
    Another intriguing 69.88-carat heliodor from the Ukraine has been fashioned into a work of art by Michael Dyber. Hemispheres of different sizes and depth are carved and polished into the back of the gem, where they act like mirrors reflecting the light. "It's a lovely and remarkable piece," Terri Ottaway said.
    An important collection of rare red beryl crystals and cut stones, donated to GIA in 2003 by Rex Harris, Michael Nielson, and Tina Nielson, all of Red Beryl Inc., was also sent to New York for the exhibit. "These crystals and faceted stones

 
 
 
  Bonham's of London recent sale of Fine Jewellery dazzled the eye. It offered collectors a plethora of period pieces. The 249 lots of sparkling jewelled delights were collectively worth nearly US$2 million.
    One of the top lots from Bonham's sale was an exquisite example of one of the most prized and desirable coloured stones of all -- the Kashmir sapphire. Mounted by the luxury jeweller Tiffany, this 18.24-carat stone showed an exceptional example of these highly coveted precious gemstones.
    Jean Ghika, Head of Bonhams Jewellery Department, said, "Kashmir sapphires are celebrated for their intensity and depth of blue colour, which at best does not diminish in artificial light. The fact that this gem-quality stone is over 10 carats and bears no evidence of heat treatment significantly adds to its rarity and value."
    The sale also featured a fine selection of diamonds, the largest weighing 10.87 carats. A Georgian diamond eternity ring, circa 1800, and a step-cut diamond single stone ring of over 5 carats were also pieces that caught the eyes of diamond lovers at the sale.
  
   
A fine Kashmir sapphire single-stone ring, by Tiffany & Co. -- the cushion-shaped Kashmir sapphire, weighing 18.24 carats, to bullet-shaped diamond shoulders, signed Tiffany & Co. -- finger size L.
 
    Those who attended the Bonhams' sale saw a beautiful early 20th century sapphire and diamond tiara with matching fringe necklace. Both are elegant and fine examples of their type, recalling the glamorous social life of a bygone era when formal jewels were essential wear for special occasions.
    The sale opened with fine examples of 18th and 19th century jewellery. Of particular note, was a mid 19th century gold, lapis lazuli and diamond necklace, brooch and earring suite, mounted by the Russian imperial jeweller Samuel Arndt, circa 1855. Arndt, whose work is rarely seen at auctions, was employed by the celebrated St Petersburg firm -- The English Shop -- who were entrusted with many important orders for the Imperial Court.
 
     Also included in this sale were jewels with a royal provenance. A late Victorian sapphire and diamond 'Lucky Horseshoe' brooch/ pendant, was a personal gift from Queen Mary to a member of her household, and is accompanied by a Christmas card from the Queen inscribed "Victoria Mary, Xmas 1899" and on the reverse "with my best wishes." There were also royal presentation brooches and cufflinks, both bearing the ciphers of King George V and Queen Mary.
     Art Deco burst into the Bonham's sale with a riot of colour and geometric design. A diverse range of brooches, pendants, rings, clips and watches displayed a combination of precious and semi-precious stones and striking colour combinations. Pieces such as a gem-set and diamond lapel watch brooch, circa 1925 would not have looked out of place adorning today's stylish women.
     The sale concluded with more modern and contemporary pieces. A highlight a colourful and highly versatile multi gem-set necklace circa 1950, designed in the form of a stylised garland, which is detachable to form a bracelet, pair of earrings and two brooches. Other jewellery from the sale that appealed include a selection of pieces signed by some of the most high fashion jewellers, including Bulgari, Cartier, Chopard, Lacloche, Marchak, Mauboussin, Tiffany and Harry Winston.
  
   
Belle Epoque sapphire & diamond fringe necklace, the curving openwork plaque designed as a garland with a sapphire & diamond floral cluster at the centre, supporting a graduating fringe of articulated drops each with a sapphire & diamond floral termination, millegrain-set throughout with circular & mixed-cut sapphires & old brilliant, single & rose-cut diamonds -- diamonds approximately 19.00 carats total.
 
     Bonham's, founded in 1793, is one of the world's oldest and largest auctioneers of fine art and antiques. Today, Bonham's is the third largest and fastest growing auction house in the world. It offers more sales than any of its rivals, through two major salerooms in London: New Bond Street, and Knightsbridge, and a further 10 throughout the UK. Sales are also held in San Francisco, Los Angeles and Boston in the USA; and Switzerland, Monaco, and Australia.
www.bonhams.com.
   
 
         
 
 
 
A mid-19th century gold, lapis lazuli & diamond necklace -- mounted by Russian imperial jeweller Samuel Arndt, circa 1855.
 
A diamond & ruby feather brooch, by Marchak, circa 1945. The taperedquill of articulated woven strands, highlighted by graduated brilliant-cut diamonds & pear-shaped rubies, signed Marchak Paris & numbered, French assay marks, length 11.0 cm.
  
 
 
  A late Victorian sapphire & diamond 'Lucky Horseshoe' brooch/pendant, circa 1895, was a personal gift from Queen Mary. Designed as a horseshoe, set with cushion-shaped sapphires & old brilliant & rose-cut diamonds.   A colorful & highly versatile multi gem-set necklace, circa 1950, designed in the form of a stylised garland.  
 
   
 
        Issues regarding diamond cut, particularly the relationship between a round brilliant's proportions and its appearance, have captured the attention of many in our industry during the last decade. Although some believe that only certain narrow proportion parameters yield the best appearance, cut has remained the least understood element of diamond quality. During this time, the Gemological Institute of America (GIA) has worked to determine what it takes to produce an attractive, lively diamond. The Institute's 15 year research project has examined the intricate and complex relationships among the various factors that lead to a diamond's face-up appearance and identified the aspects that are essential to good cut quality.
         The article in the Fall 2004 issue of Gems & Gemology, "A Foundation for Grading the Overall Cut Quality of Round Brilliant Cut Diamonds" by T. M. Moses et al., ties the various elements of GIA's study together to outline the scientific basis for a diamond cut grading system. The key results of this study bring to fruition the previous GIA reports on brilliance (in the Fall 1998 Gems & Gemology) and fire (in the Fall 2001 Gems & Gemology). Some of the main findings from GIA's research discussed in the new article are:
         - Proportions need to be considered in an interrelated manner. The combination of proportions is more important than any individual proportion value.
         - Attractive diamonds can be manufactured in a wider range of proportions than would be suggested by historical practice or traditional trade perception.
         - The quantity and quality of brightness (as brilliance is now called) and fire are only part of overall diamond appearance. The pattern of bright and dark areas within a diamond (the basis of scintillation) must be considered as well.
         - A thorough cut grading system needs to consider the design of a polished diamond (as evidenced by its weight ratio and durability) and its craftsmanship (as evidenced by its polish and symmetry).
         - Viewing environment plays an important role in diamond appearance: to be attractive, a diamond should look good in realistic environments.
         - Personal and international market preferences should be accounted for. Diamonds with different appearances can be found within each cut grade, so individuals need to look at the diamond itself, not just its grade, to choose the one they like best.

Results from Computer Modeling & Observation Tests

         The GIA researchers based their findings on the results of the two main parts of the research project: computer modeling to predict which sets of proportions would yield the best results under specific lighting conditions; and extensive visual preference tests conducted with a wide variety of trade and non-trade observers to determine the ability to consistently discern face-up appearance aspects (brightness, fire, and scintillation) and the importance of other cut quality components (such as durability and finish).