Stuart Robertson is vice president of Gemworld International, Inc. He is also research director for the company’s gemstone pricing products. Stuart is an award-winning appraiser and gemologist. He is the supervising appraiser at Gemworld. Today, his appraisal assignments are generally limited to important gemstones and expert witness services.

Richard Drucker is the president of Gemworld International, Inc. He is the publisher of the GemGuide, an international publication assisting appraisers and jewelers in pricing diamonds and gemstones. He has been retained as an expert in areas involving valuation. He also assists in corporate auditing of inventory for financial institutions. His current role in appraisal services is primarily as a consultant.

Çiğdem Lüle, is an award-winning gemologist regarded for her knowledge of gems, especially those utilized by ancient cultures. She is also an experienced mineral collector and has collaborated on appraisals of important mineral collections for museums and private collectors. As a former gemology instructor at GIA London, Dr. Lüle has a strong foundation in the identification side of appraisal work. Her trade experience with gemstones and minerals also offers an important framework for understanding the concepts associated with real world pricing research.

Trained as a geo-engineer and having earned her PhD. in Mineralogy, Hacettepe University, Turkey, 2006, Çiğdem frequently assists members of Gemworld’s appraisal team with identifying and grading rare gems and minerals.