ADAMAS GEMOLOGICAL LABORATORY
publishes gemologically oriented software for the jewelry appraiser, jeweler,
or student in gemology or mineralogy. The laboratory also provides technical
consulting and jewelry appraisal services to the trade and the public and
expert witness services to the legal profession.
Adamas Gemological Laboratory
Transmittance Data on De Beers' Synthetic Diamonds
Courtesy of the Jewelry Council of South Africa Diamond Certification
Laboratory and De Beers, Adamas Gemological Laboratory was given access
to six round brilliant cut De Beers' synthetic diamond samples. These were
tested on the Jewelry Council of South Africa Diamond Certification Laboratory's
Spectrophotometer Analysis System. The transmittance data
for these data are shown below.
Figure 1 shows transmittance data taken on sample SYN106-16, a 0.51ct
yellow round brilliant cut synthetic diamond. The transmittance data is
compared to an HRD certified Z master, the defined breakpoint between Z
color and fancy yellows. Note the absence of the nitrogen absorption system
(415nm, 430-480nm) characteristic structure shown in the Light Fancy Yellow
Master, which is a typical "cape series" diamond.
Figure 2 illustrates the transmittance of a De Beers' synthetic Blue diamond,
SYN93-4, Type 2b, electrically conductive. It might be noted that
you may be able to use your diamond thermal conductance tester as an indicator
of Type 2b stones, as, to my knowledge, at least Presidium diamond testers
sound a buzzer if they contact the hand held mounting. The electrical conductivity
of Type 2b diamond is better than human tissue, which the current must
pass through to initiate the buzzer warning.
Figures 3 and 4 show transmittance characteristics for two brown synthetics
supplied by De Beers.
Figures 5 and 6 characterize the transmittance of two near colorless synthetic
diamonds supplied by De Beers. Both lack the characteristics of the "cape
series" masters shown for comparison.