What are the 4Cs? Report Check Submit A Gem LIST YOUR STORE GIA Store My GIA MENU Gem Encyclopedia Analysis & Grading Education Alumni Research & News About GIA Frequently Asked Questions What are the 4Cs? Color, Clarity, Cut and Carat Weight are collectively called the 4Cs of diamond quality. Color measures a diamond’s absence of color. Clarity considers a diamond’s inclusions and blemishes and how they affect its appearance. Cut describes the diamonds fire, brilliance and proportions. Carat weight is the measurement of how much a diamond weighs in metric carats. Learn more about the 4Cs. Related FAQs What is the GemPass redemption program? CONTACT US TOLL FREE 800-421-7250 EXT 7590 OUTSIDE U.S. & CANADA 760-603-4500 EXT 7590 CONTACT US You Might Also Like AJP®: New 5-Day Program Offered Worldwide Learn More GIA NextGem™ Diamond Training for Retail Learn More Explore GIA Laboratory Promotional Offers Learn More Shop the GIA Store SHOP NOW Back to Top Gem Encyclopedia Education Research & News Analysis & Grading About GIA GIA Instruments Retailer Support GIA Store FAQs Pressroom GemKids Website Alumni Collective Quality Assurance Benchmarks for Jewelry 4Cs of Diamond Quality Student Consumer Information Gem & Jewelry Careers Careers at GIA Locations Report A Concern Support GIA Contact Us Developer APIs Email Preferences Cookie Preferences Download the New GIA App Follow Us Change Language: ENENEnglish (US) CN简体中文 JP日本語 Copyrights and Trademarks | Privacy Notice | Terms of Use | Cookie Notice | Ethics and Compliance | Transparency in Coverage Rule | About This Site © 2002 - 2026 Gemological Institute of America Inc. GIA is a nonprofit 501(c)(3) organization. All rights reserved.