AGSL. The American Gem Society Laboratories — a US grading lab known for its proprietary 0-to-10 cut grading scale, often considered the most rigorous in the industry. AGSL reports are treated as comparable to GIA by most US buyers.
AGSL closed its lab operations in 2022 and transferred its grading work to GIA. Existing AGSL reports remain fully valid and are still accepted at parity with GIA in the resale market.
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