AGS Certified Diamonds

Is AGS Certification the Right Choice?

The American Gem Society (AGS) pioneered the 0-to-10 scale for cut grading (where 0 is Ideal) and was historically the gold standard for light-performance grading. AGS was acquired by GIA in 2022, so new AGS certificates are increasingly rare. But existing AGS-graded stones are still widely respected, particularly by cut-quality purists.

Stones carrying a AGS certificate trade at about a 297.1% premium over the market baseline in our data. That's the 'GIA effect' at work. Buyers trust the grading rigour and are willing to pay for it. If you're going to resell the stone or want the most conservative paper trail, the premium is real and worth considering.

AGS certificates cover 1,339 listings in our database, and the mix skews heavily natural, 1,278 natural stones versus 61 lab-grown. That's the classic pattern for long-established gemological labs whose reputation was built around natural diamond grading.

Most of the AGS-certified inventory we track is in CUSHION (410 listings). Consistent with round being the default for engagement-ring buyers. If you're shopping fancy shapes, selection thins out quickly across every lab; widening your search to two or more certificate issuers often doubles the available inventory.

Existing AGS-graded stones. Especially AGS 000 (Ideal cut, polish, symmetry). Are premium inventory and often the cream of the market. Expect to pay a small premium for an AGS 000 certificate versus GIA Triple Excellent, but for cut-quality focused buyers it's worth it. New AGS reports are rare post-acquisition; most stones are now being graded under GIA.