This year’s Institute of Registered Valuers’ Conference was again held at Loughborough University, on Sat 19^th to Monday 21^st September. The conference’s major aim is to act as venue where jewellery valuers and others (including gemmologists such as me) can meet, attend informative lectures and workshops and discuss matters of mutual concern. Although the theme of this year’s meeting was the assessment of colour qualities and values of coloured stones, the conference was divided into two: main presentations where all participants can attend, and a number of workshops, such as antique jewellery, jadeite, and precious stone price lists, coloured stone grading methods, Chinese wristwatches and valuation processes. Naturally I chose workshops relevant to precious gems.

In the first main presentation Tracy Jukes of the coloured stone dealers, e-Jewel, summarised the current gem scene. She reviewed her trip to Tucson 2009, while noting a 40% drop in business at the shows, she emphasised the show is still worth attending for gem pricing information and noting the extent of stones on sale. More synthetic gems, simulants and coated stones were noticeable with Chinese vendors selling very cheap jewellery. She thought the shows were now more of a retail event where one can only buy on cash terms with US dollars. In the Gem District of Bangkok, Thailand, she saw an 80% drop in business, although gem prices have increased. Tracy illustrated the forms of gem treatments associated with heat. She showed slides of surface diffused corundum, bulk diffused examples, trading at 70% discount, glass-filling with a borosilicate ‘flux’, and lead-glass filling of gems where 20% of the gem’s weight could be the glass filler. She summarised one US gem laboratory’s description of the treatment at made reference to CIBJO’s ruby and sapphire guides. She briefly dealt with the current issue of emerald treatments, synthetic gems, simulants and coated stones. The importance of correct gem description (pink sapphire vs. ruby, and green beryl vs. aquamarine) and the definition of Paraiba tourmaline were briefly reviewed. The latest gem localities were summarised: sources of Tanzanian zircon, spinel, emerald and chrysoberyl; Nigerian tourmaline, Namibian demantoid garnet, Zambian pink and yellow tourmalines, Tanzanian rubies from Songea and Winza, Mozambique rubies and Madagascan sapphires were discussed. Tracy spoke of an 80% drop in Tanzanite production in the last 12 months, and finally fire quartz and sunstone, similar in appearance, were illustrated.