Hallmark Research Institute
 Dedicated to education and understanding in precious metal hallmarks around the world

Author Bios

William Whetstone - historian, antiquarian jeweler, numismatist, educator, goldsmith. Mr. Whetstone has been a dealer and collector of ancient and world coins, as well as precious metal objets d’art for over forty years. A graduate with honors in history from McGill University, Mr. Whetstone was a former director and twice past president of the International Society of Appraisers (ISA), where he wrote the first technical Canadian course for professional personal property appraisers, lecturing on various topics in gems and jewelry, and residential contents and fine arts, both in the USA and Canada. Whetstone, who has been teaching the analysis of hallmarking for the past fifteen years, joined with Danusia Niklewicz and Lindy Matula to bring his years of expertise as a historian in analyzing, researching, and documenting world hallmarks to the writing this comprehensive publication.... "They made me do it ...and I thank them very much."


Danusia Niklewicz, GG, FGA, ISA-CAPP, ASA educator, appraiser, gemologist, jeweler, goldsmith. Ms. Niklewicz has been involved in the jewelry industry for over thirty years. From bench jeweler to Graduate Gemologist of the Gemological Institute of America (GIA), she earned her Fellowship from the Gemmological Association of Great Britain (GA) while a part of the GIA international teaching staff. From there, Niklewicz turned her focus to valuation by earning titles from the International Society of Appraisers (ISA) and the American Society of Appraisers (ASA), to become a respected independent jewelry appraiser to the antique and high-end jewelry community in Los Angeles for over twenty years. Ms. Niklewicz continued teaching and creating appraisal seminars for GIA, ISA and Insurance Education Association (IEA). Currently, Danusia Niklewicz and William Whetstone conduct an interactive lecture series on hallmarks of precious metals to industry professionals and collectors across the USA and in Canada. Niklewicz brings to this publication her years of experience in jewelry, researching, course writing, international collaboration, graphics, and visual arts to present a new understanding of hallmarking through methodology and imagery.


Lindy Matula, GG, ASA appraiser, educator, gemologist, jeweler, goldsmith. Ms. Matula has been involved in the jewelry industry for nearly thirty-five years. Matula worked as a goldsmith prior to receiving her Graduate Gemologist degree from the GIA. Through the years Ms. Matula has been involved in the jewelry industry as a goldsmith, an investment diamond grader, wholesaler, appraiser, contemporary jewelry gallery manager, and instructor at the Revere Academy. Following her position as head gemologist for Butterfield's & Butterfields auction house, she aligned professions with Danusia Niklewicz in 1990 to create the networking appraisal group, Paradise Associates. Matula is currently the top independent appraiser of antique, contemporary and fine high-end jewelry in the San Francisco Bay Area. Lindy Matula brings orchestration to this massive, multi-year project that has been vital to the completion of this first in a series of volumes designed to lift the veil of complexity on modern and historic hallmarks.


Whetstone, Niklewicz, and Matula are the Founding Directors of the Hallmark Research Institute (HRI), and dedicated to furthering the understanding of precious metal hallmarks from around the world. Along with their research, HRI conducts lectures and educational seminars on hallmarks and are advocates for the promotion of global hallmarking.

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