ISO 24016-2020 PDF

Full title and description

ISO 24016:2020 — Jewellery and precious metals — Grading polished diamonds — Terminology, classification and test methods. This International Standard defines terminology, classification categories and test methods used when grading and describing single, unmounted, polished natural diamonds over 0.25 carat (ct).

Abstract

This standard specifies the terminology, classification and the methods that are used for the grading and description of single unmounted polished diamonds over 0.25 carat. It applies to natural, unmounted, polished diamonds and expressly excludes fancy‑coloured diamonds, synthetic diamonds, treated diamonds (except as allowed in clause 7.4) and assembled stones.

General information

• Status: Published
• Publication date: 18 September 2020 (ISO publication: 2020-09; published 2020-09-18)
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 39.060; 01.040.39
• Edition / version: Edition 1 (2020); corrected version issued March 2024
• Number of pages: 53

Key bibliographic facts above are taken from the ISO record for ISO 24016:2020 (including the 2024 corrected version).

Scope

ISO 24016:2020 applies to the grading and description of single, unmounted, natural polished diamonds of more than 0.25 ct. The standard defines the terms to be used, classification categories and the specific test methods for assessment. It is not intended for fancy‑coloured diamonds, synthetic diamonds, treated diamonds (except where clause 7.4 permits) or assembled stones. The document is intended to harmonize grading language and procedures used by laboratories, traders and regulators when describing polished natural diamonds in the stated size range.

Key topics and requirements

• Standardized terminology for describing polished diamonds (definitions for clarity and consistency).
• Classification schemes and grading categories applicable to single unmounted polished natural diamonds > 0.25 ct.
• Prescribed test methods and procedures to be used when grading and describing stones (inspection conditions, instruments, measurement practice and reporting items).
• Exclusions and special cases: fancy‑colour, synthetic, treated (except where explicitly allowed), and assembled stones are excluded from the main scope.
• Requirements for reporting and labelling of graded stones to promote comparability between grading reports and laboratories.

Typical use and users

Primary users include gemmological and diamond grading laboratories, independent graders, jewellery manufacturers, traders, retailers, assay and hallmarking bodies, standards organizations and regulators involved in consumer protection or market surveillance. The standard is used to harmonize grading language in reports, improve comparability of grading results between labs, and support clear communication to customers and downstream supply‑chain actors.

Related standards

Closely related ISO deliverables include ISO 18323:2015 (Jewellery — Consumer confidence in the diamond industry), which provides permitted descriptors and nomenclature for natural, treated and synthetic diamonds; and general laboratory competence standards (for example ISO/IEC 17025) used by grading laboratories. National and regional adoptions or EN/DIN translations of ISO 24016:2020 and its corrected version also exist.

Keywords

diamond grading; polished diamonds; terminology; classification; test methods; natural diamond; unmounted stones; gemmological reporting; ISO 24016

FAQ

Q: What is this standard?

A: ISO 24016:2020 is an International Standard that defines terminology, classification and test methods for grading single, unmounted, polished natural diamonds larger than 0.25 carat.

Q: What does it cover?

A: It covers standardized terms, grading categories and specified methods and conditions for assessing and reporting the characteristics of single unmounted polished natural diamonds (>0.25 ct). It excludes fancy‑coloured diamonds, synthetic diamonds, treated diamonds except where clause 7.4 permits, and assembled stones.

Q: Who typically uses it?

A: Gemmological laboratories, diamond graders, jewellery manufacturers and retailers, assay and hallmarking bodies, standards bodies and regulators — anyone needing a harmonized approach to grading and reporting polished natural diamonds in the stated size range.

Q: Is it current or superseded?

A: The document was published in September 2020 and remains the current ISO publication; a corrected version was issued in March 2024. The ISO record shows the standard as published and under routine review cycles.

Q: Is it part of a series?

A: It sits within ISO/TC 174 (Jewellery and precious metals) deliverables and complements other diamond/jewellery standards such as ISO 18323:2015 (consumer confidence in the diamond industry) and national/regional adoptions or translations of these ISO standards.

Q: What are the key keywords?

A: Grading, polished diamonds, terminology, classification, test methods, natural diamond, unmounted, gemmological reporting (ISO 24016:2020).