Gemologist and author Richard Hughes has resigned as senior staff gemologist for the American Gem Trade Association's Gemological Testing Center. Hughes worked at GTC for four years in the West Coast laboratory. Hughes will work with Loretta Castoro, also a former AGTA-GTC employee, at Gems TV, the on-air television gem sales company based in Singapore, with offices in Bangkok, Thailand. Hughes's wife, Wimon, is from Bangkok. Hughes will be involved in marketing and will help train Gems TV's on-air presenters. He also will work with the staff on how to properly identify gemstones when buying. Hughes is the author of the self-published Ruby & Sapphire and has written more than 100 articles on various aspects of gemology.