TS EN ISO 24016

TS EN ISO 24016 is the standard for the terminology, classification and test methods used to grade and describe single unmounted polished diamonds. In jewellery and gemological trade, grading depends on a shared way of describing a stone’s observable and measurable characteristics. This standard focuses on polished diamonds over 0.25 ct, giving users a common framework for evaluation and description.

How the grading language is organised

For polished diamonds, grading is not only about the stone itself but also about the meaning of the terms used to describe it. In general technical practice, terminology standards reduce ambiguity between laboratories, traders and appraisers by aligning the names and definitions of grading features. That matters because diamond descriptions often combine several attributes, such as appearance, measurable characteristics and classification categories, and those terms must be interpreted consistently.

What this document covers and excludes

• Applies to natural, unmounted, polished diamonds.
• Covers single stones over 0.25 ct.
• Not intended for fancy coloured diamonds.
• Not intended for synthetic diamonds.
• Not intended for treated diamonds, except as allowed in 7.4.
• Not intended for assembled stones.

As a general technical reference, this standard supports consistent grading and description rather than replacing professional judgement. It is used in the context of gemological assessment and jewellery commerce where comparable terminology and methods matter. The inclusion of the corrected version dated 2024-03 indicates that this edition reflects the corrected ISO text.