- > Gems & Jewellery
- > Journal of Gemmology
- > Ordering Back Issues of the Journal
- > Samples
- > The Journal online
- > Issues 2008 to date
- > Schmetzer, 2010
- > Volume 31, Nos 1-2, 2008
- > Li Jianjun et al 2010
- > Sturman Teaching
- > Sturman and Parker optic sign
- > Sturman and Parker shadow edges
- > Schmetzer, Chrysoberyl, 2011
- > Andersson, Maxixe beryl, 2011
- > Schmetzer trapiche tourmaline
- > Duroc Danner
- > Schmetzer Lake Manyara
- > Pearson Ultraviolet sources
- > Ostrooumov and Morales 2010 (1)
- > Bidney et al., 2010
- > Kitawaki et al., 2010
- > Hänni et al., 2010
- > Volume 31, Nos 5-8, 2009
- > Hainschwang 2010
- > Vol. 31, Nos 3-4, 2008
- > Cowing, 2010
- > Issues prior to 2008
- > Submitting Articles for the Journal
- > Direct Subscribers
The over-grading of blue-fluorescent diamonds: the problem, the proof and the solutions
Michael D. Cowing
Abstract: Decades after the establishment in the mid-twentieth-century of ultraviolet-free illumination for colour grading a diamond, an examination of diamond trade and laboratory grading practices finds nearly everyone employing some type of fluorescent tube lighting containing significant ultraviolet. This paper demonstrates and quantifies the over-grading of blue-fluorescent diamonds that often can result. Simple methods are proposed that, by themselves or in combination, provide inexpensive and workable solutions to resolve this problem.
All the Journal articles placed online in 2010 will also be published in hard copy as a single Journal issue and sent to all paid-up Gem-A members early in 2011 as part of their 2010 subscription. Gem-A members may login to the membership area to view the full articles.
