Gemstone Valuation & Grading
Houses have deeds. Vehicles have titles and registrations. It only makes sense that you have similar documentation for something as precious as a gem purchase.
A report from GIA is an expert statement of a gem’s identity and quality characteristics. A GIA report isn’t an appraisal of financial value; it’s is your assurance of your gemstone’s quality, with clear disclosure if the material is laboratory-grown or if it has been treated to enhance or alter its appearance. The report provides the kind of evidence that is vital to a confident gem or jewellery purchase.
A non-profit, public benefit research and educational institution, GIA is as an independent and impartial entity for evaluating the quality of gems and delivering unbiased information on them. We do not sell gemstones, nor do we represent the interests of gem sellers.
People from all over the world rely on GIA when it comes to identifying and evaluating gem materials.
Here are some reasons why:
Research – GIA has the world’s most comprehensive gemmological research program; a staff with academic training and gem-testing experience; modern scientific instrumentation; and a superb collection of gem materials. For more than 80 years, GIA researchers have studied the scientific properties of gems to develop new methods of identifying natural, laboratory-grown and treated gems. Results of these studies are incorporated into GIA educational materials and are published in professional journals. And they inform the grading and analytical methods we use in our laboratories.
Detection – Our laboratories examine more than two million diamonds, coloured stones, and pearls each year. The data we collect forms the basis of our ability to detect new gem materials entering the marketplace.
Standards – GIA developed and maintains the methods and best practices for evaluating diamonds, coloured stones and pearls. As creator of the 4Cs and the GIA International Diamond Grading System™, we established the common language for describing the quality of D-to-Z colour diamonds. We also developed the terminology and methodology for evaluating coloured diamonds, and the classification standard for natural and cultured pearls – the 7 Pearl Value Factors™.
Instrumentation – Detecting today’s increasingly sophisticated laboratory-grown and treated gems require examination using highly advanced scientific instruments. GIA laboratories are equipped with powerful analytical tools similar to what can be found only at leading universities and national laboratories. This equipment allows us to examine material at high magnification in order to document gemmological properties, chemical composition, spectral features, and other characteristics.
Accuracy and Consistency – Every GIA laboratory operates under the same set of standard procedures and principles designed to ensure the objectivity and accuracy of every gem identification or grading report issued. These tenets are supported by research, highly trained staff, state-of-the-art security and monitoring features, and a suite of best-practices.
Global Database – Gem grading and identification records are archived in an extensive global database for ongoing study and future reference. This information gives GIA the ability to identify items that have been submitted to us previously for examination, and to assist law enforcement agencies from around the world in the recovery of stolen goods.
Famous Diamonds Graded by GIA – We’ve been entrusted with grading some of the world’s most famous diamonds, including the Hope (45.52 carats), the Steinmetz Pink (59.60 carats), the Taylor-Burton (69.42 carats), the Allnatt (101.29 carats), the De Beers Millennium Star (203.04 carats), the Centenary (273.85 carats), and the Incomparable (407.48 carats).