Grading the Colorful, The Rocky Road to Quality Assessment
by Richard W. Wise, G.G.
“Collectors Universe has stated it has every intention of becoming the world's leading purveyor of diamond and colored stone pedigrees—"maybe not tomorrow, or next year," (CU President) Haynes says, "but within the foreseeable future."
David Federman, Professional Jeweler, 2006
At the beginning of a new year it is traditional to assess the past year, make resolutions and talk about the future. Several happenings over the past twelve months that considered in isolation are important taken as a whole appear to be crucial milestones along the road toward colored gemstone quality grading.
A consortium of seven major gem laboratories under the aegis of the Laboratory Manual Harmonization Committee (LMHC) established important precedents:
- First, they abandoned the traditional protocol of naming a gem based on species and variety. The committee agreed that on grading reports issued by member labs to use the term “
Paraiba” to describe all copper colored or cuprian tourmalines regardless of their actual source.
- In a separate decision, the LMHC also decided to stray beyond the realm of verifiable science and enter the world of aesthetics. They agreed to adopt a set of color parameters for and use the term “Padparadscha” sapphire on grading reports issued by member labs.
This year a new player entered the grading games: Collectors Universe (CU), a publicly traded company that provides certification for coins stamps and guess what, baseball cards purchased American Gemological Laboratories (AGL) the only major
In order to have a universal colored stone grading system you must have a universally acceptable methodology. Internet shoppers, in particular, are demanding a way to compare apples to apples and what the market requires the market sooner of later gets. Getting all major players to accept a single methodology may be difficult but a broad basis of agreement between a number of important labs may do the trick. The LMHC includes seven of the world’s most respected gemological laboratories: (
Historically, no institution, not even the mighty Gemological Institute of America (GIA), the originator of the universally accepted diamond grading system, has succeeded in creating an acceptable colored stone grading system. GIA tried twice, first in the 80s Colormaster, a sort of color blender and then with Gemset, a set of round faceted plastic doohickeys, both of which were flawed and failed to win industry wide acceptance. GIA has wisely abandoned its go it alone strategy and joined LMHC.
Instrument based color determination appears to be the wave of the future. According to American Gemological Laboratories C. R. “Cap” Beasley “instrument based measurement is simply more consistent”. The fact is; you have the rock, the light and the observer, standardize the latter two and you are eliminate two variables. Does Beasley have an instrument? None that he will admit to.
AGL is still the only major laboratory that grades colored gemstones. Beasley introduced his own system, Colorscan, in the early 1980s, a system that many gemologists including this writer believes was the most viable system yet created. Colorscan, however, relied on the human eye as observer. New Computer based systems such as Gem-e-Square that project a range of hue/saturation/tone on a color computer monitor also require the human eye and judgment to make a call.
Collectors Universe appears to be making a bid to become a major player in quality grading. I will be interviewing CU president Bill Haynes, later in the week. Stay tuned.
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The Hope Diamond, Inflation in the Seventeenth Century
In 1669 Louis XIV of France purchased the French Blue diamond from the famous gem merchant Jean-Baptiste Tavernier for 220,000 livres or 42.7 million dollars (1 livre = $1,941.). In an inventory taken by the French crown in 1691 the Sancy Diamond, a colorless stone of 55.23 carats and the largest white diamond in Europe at that time, was valued at 24.2 million dollars.
By the time this inventory was taken, The French Blue, had been recut by M. Pitau to 69 carats, a 40% loss in weight. Despite this the stone that ultimately became the Hope Diamond, was valued at…in 1691? The first person who comes closest wins a signed paperback copy of Secrets Of The Gem Trade. Post your answer in French livres and your email address to the Comments section of the blog. Winner’s name to be posted on GemWise in two weeks. Hint: read Ronald, The Sancy Blood Diamond, Morel, The French Crown Jewels