Shane McClure Reveals Fascinating Finds from the GIA Lab

Shane McClure
Shane McClure, GIA's director of West Coast identification services, regaled AGS Conclave attendees with some of the unusual cases that have crossed his desk.
GIA’s founding father Robert Shipley had a groundbreaking 1934. In addition to launching Gems & Gemology, he established the American Gem Society (AGS) with the intent of promoting professional ethics and continuing education for those in the gem and jewellery industry. In keeping with Shipley’s vision, AGS’ annual Conclave celebrated the society’s 80th year from 23-26 April at San Diego’s Hotel del Coronado, hosting numerous educational seminars, presentations and networking opportunities. On Thursday 24 April, Shane McClure, GIA’s director of West Coast identification services, presented “A Day in the Life of a Laboratory Gemmologist”, exploring the work he has undertaken during his years with the Institute.
McClure compared his role to those of a detective and a forensic scientist, explaining that frequently lab staff must take an unknown material and figure out what it is, while also determining whether the material has been treated. The lab sees specimens that run the spectrum from very rare material to items people find in their own backyards that they hope will prove valuable. McClure considered some of the more unusual cases that he had seen in his years at GIA, discussing interesting identification situations, composite materials, and scams.
Among the identification highlights were a specimen that was sent to the lab as possible opal that turned out to be a piece of bowling ball; a material called “rainbow calsilica”, reputedly from Mexico, from which the lab removed a piece of a soda bottle; and a sapphire inclusion in a diamond. The latter is now owned by GIA and housed in their reference collection. McClure also referenced a diamond scalpel, that was identified as a CVD grown synthetic diamond, as well as a piece of charcoal that the owner believed might be a black diamond.
According to McClure, composite materials are becoming more common. This may be a result of the rising price of gems coupled with the quantity and low prices required by TV shopping networks for large-scale sales. While the lab most frequently saw such situations in ruby and turquoise, an unusual case involved a pink and green tourmaline held together with plastic.
McClure also discussed specific scams that had come to the attention of the lab during his tenure; for example, so-called “sapphires” and “rubies” that were supposedly worth millions, if not billions of dollars, in some cases using questionable appraisal reports. GIA’s labs saw these cases throughout the 1970s and 80s. He also cited misrepresentations, such as non-identification of treatment. In one instance, the lab received purple opal, supposedly from Kenya or Mexico. Creative testing methods revealed that the opal was from Ethiopia, and had in fact been dyed to appear purple.

McClure closed his presentation with the hot topic of jade nomenclature. He explained how the discovery that another pyroxene mineral called omphacite can be virtually identical in appearance, colour and properties to jadeite, is causing trade experts to reconsider what materials may be defined as “jade”. GIA itself, he noted, has begun to identify some omphacite as “omphacite jade” on reports.

McClure’s experience provides trade members with greater insight into the curiosities lab personnel encounter, and the innovative solutions they implement, during the course of their work. 

Jennifer-Lynn Archuleta is the associate editor of Gems & Gemology in Carlsbad, California.