Overview
SIST EN ISO 23345:2026 specifies a standardized, non-destructive method for verifying the fineness of precious metals in finished and semi-finished jewellery items using energy-dispersive X-ray fluorescence (ED-XRF). Developed by CEN and aligned with ISO 23345:2021, this standard supports quality assurance and compliance for stakeholders in the jewellery and precious metals industry. The method applies to homogeneous items, explicitly excluding any coated pieces, and cannot be conducted with WD-XRF (wavelength dispersive XRF) equipment.
Key Topics
- ED-XRF Technique: Energy-dispersive X-ray fluorescence enables rapid, non-destructive elemental analysis, making it ideal for confirming metal composition in jewellery without damaging valuable pieces.
- Sample Suitability: The method is intended exclusively for homogeneous precious metal items and is not suitable for plated or coated jewellery. Proper sample preparation, including surface cleaning, is required for accurate results.
- Calibration and Verification: Accurate calibration is fundamental. The procedure requires the use of at least three calibration standards with known compositions that closely match the sample’s alloy makeup and a separate reference material to verify calibration.
- Analysis Process:
- Analyze multiple points on each sample to ensure reliability.
- Calculate mean values and assess measurement uncertainty.
- Validate results according to specified tolerances and conformity ranges, referencing ISO 10576-1 for decision rules.
- Reporting Requirements: The standard details the essential information to include in test reports, such as sample identification, applied standard reference, test results, deviations from methods, unusual observations, laboratory details, and responsible signatures.
Applications
SIST EN ISO 23345:2026 is vital for:
- Jewellery Manufacturers: Confirms the declared fineness of precious metal items quickly and non-destructively, supporting quality control processes.
- Precious Metal Assayers: Offers a standardized, recognized technique for verifying metal content in routine examination of goods.
- Customs and Trade Authorities: Ensures jewellery traded across borders meets harmonized European and international standards for precious metal content.
- Third-party Laboratories: Provides a clear method for delivering impartial verification services to jewellery producers and retailers.
- Retailers and Brands: Supports claims of fineness and metal composition, enhancing consumer trust and compliance with regional regulations.
The method is valuable when destruction of samples is not an option due to value, uniqueness, or other considerations.
Related Standards
- ISO 9202: Jewellery and precious metals – Fineness of precious metal alloys: Defines permissible alloy compositions and fineness standards.
- ISO 10576-1: Statistical methods – Guidelines for the evaluation of conformity with specified requirements: Establishes general principles for conformity assessment.
- ISO 11426: Jewellery and precious metals – Determination of gold – Cupellation method (fire assay): Provides the traditional, destructive assay method for gold content, used when higher precision is necessary.
- ISO 17034: General requirements for the competence of reference material producers: Relevant for the selection and use of certified reference materials in calibration and verification.
SIST EN ISO 23345:2026 helps the jewellery and precious metals sector achieve non-destructive, efficient, and internationally recognized verification of precious metal fineness, enhancing transparency and reliability in global commerce.