The Amsterdam diamond cutter Moses Elias Coster moved into factory premises at Waterlooplein in 1840, and Coster Diamonds was born. During that time, diamonds were still cut by machines literally powered by horses. Today, they are located in three grand mansions, beautifully situated between the Rijksmuseum and the Van Gogh Museum. They sell loose & set diamonds as well as offer a Coster Diamond Certificate which will assure you of the authenticity and quality of your diamond.
The American Gem Society Laboratories is the premier diamond-grading laboratory in the world. Founded 1996, the American Gem Society Laboratories was established to fulfill a need in the industry?to provide you with a protective and definitive diamond- grading document. The American Gem Society Laboratories? diamond grading reports quantify a diamond?s beauty using a 0 to 10 grading scale created for simplicity and ease-of-use.
Consumer Protection Since 1934 ?. When you work with members of the American Gem Society, you?re working with knowledgeable and credentialed experts in gems and jewelry who adhere to the highest ethical and professional standards. Only 5% of jewelers, designers, appraisers, and suppliers nationwide have met the exacting standards for membership in the American Gem Society, and all titleholders must be recertified annually! Shop with the best ? a jewelry expert and member of the American Gem Society.
One of the leading trade organizations and gem/diamond testing laboratories and member of the The Laboratory Manual Harmonization Committee (LMHC). The AGTA Gemological Testing Center is the natural colored gemstone industry?s premier independent laboratory providing the industry and the public with a complete range of services, including gemstone identification, origin determination and pearl identification. The laboratory, located in New York City, is equipped with the latest, technologically advanced, investigative equipment.