Diamond Quality Information
GIA Anatomy of a Diamond
The Gemological Institute of America (GIA) is the world's foremost authority on diamond and gemstones. GIA has established the internationally accepted standard for diamond grading on which Costco's standards are based.
Costco offers our members high quality jewellery at an exceptional value. Our team of GIA Graduate Gemologists inspect every diamond to ensure it meets Costco's strict quality standards. We only sell natural and untreated diamonds.
GIA 4Cs of Diamond Quality
GIA Color Scale
GIA Clarity Scale
GIA Cut Scale
Carat Weight
* All diamond images and diagrams are for reference only and may not reflect true diamond quality grades or carat weight. Images are not for use in diamond grading.
Certificates
Costco Article of Description - A detailed article of description will accompany diamond items with center stones less than 1.00ct.
Gemological Institute of America (GIA) Diamond Grading Report - All items with a 1.00 carat or larger diamond center stone will include a GIA Diamond Grading Report detailing the center diamond.
Gemological/jewellery Report - All items with a 1.00 carat or larger diamond center stone will also include a Gemological/jewellery Report describing the article of jewellery. This report will not have a monetary value listed. You can contact the the company that issued the report and request an insurance appraisal, in which case your Costco purchase price will be documented as the insurance replacement value.
Care and Maintenance
Although diamonds are one of the hardest substances on earth, they are still vulnerable to damage such as abrasion, chipping and breakage. We recommend having your jewellery inspected every 6 months by your local qualified jeweler for any needed maintenance or repair, avoid all harsh chemicals, such as chlorine or ammonia, as they may damage the metal and/or stones.