What is ISO 11426 about?
ISO 11426 discusses determination of gold through Cupellation Method. ISO 11426 specifies a cupellation method (fire assay) for the determination of gold on a material considered homogeneous. The gold content of the sample lies preferably between 100 and 999,5 parts per thousand (‰) by weight. Fineness above 999,5 ‰ can be determined using a spectroscopy method by difference.
Note 1: The procedure is applicable to most types of gold samples.
Note 2: Some modifications in ISO 11426 are indicated for specific cases (presence of many base metals, platinum or palladium, silver).
Note 3: ISO 11426 Is not compatible with the presence above trace levels of iridium, rhodium, and ruthenium (more than 0,25 ‰ for the sum of all three elements).
Note 4: The method in ISO 11426 is also intended to be used as the recommended method for the determination of fineness in jewellery alloys.
Who is ISO 11426 for?
ISO 11426 on cupellation method (fire assay) for determining gold is applicable for:
- Jewellers and designers
Why should you use ISO 11426?
ISO 1142 provides cupellation method (fire assay) cupellation is a refining process in metallurgy.
ISO 1142 provides cupellation method that helps you to determine gold, remove impurities from gold, increase the purity of gold, and refine gold, and separate copper from gold.
What’s changed since the last update?
BS EN ISO 11426:2021 supersedes BS EN ISO 11426:2016, which is withdrawn.
The main changes BS EN ISO 11426:2021 compared to the BS EN ISO 11426:2016 are as follows:
- Extension of the scope to cover the determination of gold in multiple types of alloys, not only in jewellery ones
- Specific procedures are described in clause 8 for samples with large amounts of base metals, containing platinum or palladium, or with a silver/gold ratio higher than 3
- Calculation was adapted to consider the addition of pure gold and the fineness of the gold used in the proof sample
- Repeatability requirements were changed
- The use of scarification was removed