Overview
EN ISO 8654:2018 (ISO 8654:2018) - "Jewellery - Colours of gold alloys - Definition, range of colours and designation" standardizes how the colour of gold alloys is defined, measured and designated for jewellery and related products. It applies to objects made of, or coated with, gold alloys and provides both quantitative and qualitative methods to determine and communicate colour. This European adoption supersedes EN 28654:1992 and references CIE Publication No. 15 for colourimetry.
Key topics and technical requirements
- Colour designations: Seven standard colour names and codes:
- 0N yellow green, 1N pale yellow, 2N light yellow, 3N yellow, 4N pink, 5N red, 6N dark red.
- Measurement methods:
- Quantitative: Spectral reflectance measured with an integrating-sphere spectrophotometer (measurement geometry di:8° or 8°:di), specular component included (SCI), standard illuminant D65, standard observer 2°. Average of 5 distinct measurements (reposition and rotate between each).
- Qualitative: Visual comparison using polished colour slips (preparation described in Annex A).
- Sample preparation:
- Flat, polished, defect‑free mirror surface. Metallographic preparation with final polishing on broadcloth using 1 µm abrasive; clean with microfibre cloth and isopropyl alcohol (IPA).
- Colour measurement should be taken within 120 minutes after final polishing.
- Colour spaces & tolerances:
- Nominal values and tolerances provided in xyY, CIE Lab* and LCh with specified significant digits for reporting (xyY: 4 digits for x/y, 1 for Y; Lab*: 2 digits for a*/b*, 1 for L*).
- Reference & scope: Normative reference to CIE Publication No. 15; intended to help purchasers precisely specify colour requirements without physical samples.
Applications and users
EN ISO 8654:2018 is practical for:
- Jewellery manufacturers and alloy producers - for production control and colour specification.
- Quality control laboratories and metrology labs - for standardized colour measurement and reporting.
- Retail buyers, product designers and procurement teams - to define precise colour requirements in orders.
- Coating and plating suppliers - to match substrate appearance to designated gold alloy colours.
- Regulatory or conformity assessors requiring consistent colour designation.
Using this standard reduces disputes over colour acceptance, speeds procurement, and improves traceability of colour specifications in the value chain.
Related standards and references
- CIE Publication No. 15 - Colorimetry (normative reference for measurement methods)
- ISO/TC 174 - Technical committee responsible for jewellery standards
Keywords: EN ISO 8654:2018, ISO 8654:2018, jewellery, colours of gold alloys, gold alloy colour measurement, spectrophotometer, Lab*, xyY, CIE D65, colour designation.