ISO/TC 174/WG 1 - Methods for determining fineness

This document describes a non-destructive method to verify (confirm) the precious metal fineness of finished and semifinished jewellery item(s) considered homogeneous by ED-XRF (energy dispersive X-ray fluorescence), including alloys according to ISOÂ 9202. This document is not suitable for any coated items. WD-XRF (wavelength dispersive X-ray fluorescence) equipment cannot be used.

This document 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 (e.g. ISO 15093). The procedure is applicable to most types of gold samples. Some modifications are indicated for specific cases (presence of large amount of base metals, platinum or palladium, silver). It 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). This method is also intended to be used as the recommended method for the determination of fineness in jewellery alloys covered by ISO 9202.

This document specifies the requirements, test methods, inspection, marking, packaging, transportation, storage, quality certificate and the order (or contract) information of one kilogram gold bars. This document is applicable to one-kilogram cast gold bars produced for investment markets or industrial (jewellery, electronic) markets.

This document specifies the analytical procedure for the determination of silver with a nominal content of and above 999 ? (parts per thousand). This document specifies a method intended to be used as the recommended method for the determination of silver of fineness of and above 999 ?. For the determination of fineness of and above 999,9 ?, modifications described in Annex B apply.

This document specifies the analytical procedure for the determination of gold, platinum and palladium with a nominal content of and above 999 ? (parts per thousand). This document specifies a method intended to be used as the recommended method for the determination of gold, platinum and palladium of fineness of and above 999 ?. For the determination of fineness of and above 999,9 ?, modifications described in Annex B apply.

This document specifies the precious metal content in solders suitable for use in the production of jewellery made of precious metal alloys.

This document describes an analytical procedure for the determination of platinum in platinum alloys with a nominal content up to 990 ‰ (parts per thousand), including alloys according to ISO 9202.

This document describes an analytical procedure for the determination of palladium in palladium alloys with a nominal content up to 990 ? (parts per thousand), including alloys according to ISO 9202.

ISO 11490:2015 specifies a gravimetric method for the determination of palladium in palladium jewellery alloys, preferably within the range of fineness stated in ISO 9202. These alloys may contain silver, indium, gallium, copper, cobalt, nickel, tin, and ruthenium. Coprecipitated elements have to be determined by a suitable method and a correction applied.

ISO 13756:2015 specifies a volumetric method for the determination of silver in silver jewellery alloys, preferably within the range of fineness stated in ISO 9202. These alloys may contain copper, zinc, cadmium, and palladium. Apart from palladium, which must be precipitated before commencing titration, these elements do not interfere with this method of determination. NOTE This method is an alternative recommended method to ISO 11427.

ISO 11426:2014 specifies a cupellation method (fire assay) for the determination of gold in gold jewellery alloys. The gold content of the alloys should preferably lie between 333 and 999 parts per thousand (?). The procedure is applicable specifically to gold alloys incorporating silver, copper, and zinc. Some modifications are indicated where nickel and/or palladium are present in the so-called white gold alloys, as well as for alloys containing 990 or more parts per thousand (?) of gold. ISO 11426:2014 is intended to be used as the recommended method for the determination of fineness in alloys covered by ISO 9202.

ISO 11210:2014 specifies a gravimetric method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness stated in ISO 9202. These alloys can contain palladium, iridium, rhodium, copper, cobalt, gold, ruthenium, gallium, chromium, indium, and less than 5 % tungsten. Some modifications are indicated where palladium, iridium, rhodium, gold, or ruthenium are present.

The method of ISO 11427:2014 describes a volumetric method for the determination of silver in jewellery alloys, preferably within the range of fineness stated in ISO 9202. These alloys may contain copper, zinc, cadmium, and palladium. Apart from palladium, which must be precipitated before commencing titration, these elements do not interfere with this method of determination. This method is intended to be used as the referee method for the determination of fineness in alloys covered by ISO 9202.

ISO 11596:2008 specifies a method of sampling precious metal jewellery alloys for the determination of the precious metal content. It is applicable to raw materials, semi-finished products and finished products of the jewellery alloys of precious metals. The purpose of ISO 11596:2008 is to define all the operations needed to obtain samples intended for the determination of the precious metal content of a particular jewellery alloy. It is intended to be applied when sampling alloys are claimed to be homogeneous. ISO 11596:2008 does not cover alloys of precious metals used in industrial products, coins qualified as legal tender, dentistry or decorative coatings on other material. It is not intended to apply to procedures employed for the purposes of production control or for the provision of samples other than for the determination of the precious metal content.

ISO 11211-2:2002 specifies methods for the grading of natural unmounted polished diamonds within the D to Z series and the grading criteria, other than for the colour of naturally coloured diamonds.

ISO 15093:2015 specifies an analytical procedure for the determination of either platinum in platinum jewellery alloys, gold in gold jewellery alloys, or palladium in palladium jewellery alloys, with a nominal content of each precious metal of 999 ? (parts per thousand) by measuring specific elements. (See Tables A.1, A.2, and A.3.) ISO 15093:2015 specifies a method intended to be used as the recommended method for the determination of fineness in 999 ? alloys covered by ISO 9202.

ISO 15096:2014 specifies the analytical procedure for the determination of silver with a nominal content of at least 999 ? (parts per thousand) by measuring specific elements listed in Table A.1. This International Standard specifies a method intended to be used as the recommended method for the determination of fineness in 999 ? silver alloys covered by ISO 9202.

ISO 11494:2014 describes a method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness specified in ISO 9202, by means of inductively coupled plasma optical emission spectrometry (ICP-OES). This method applies to platinum jewellery alloys that might contain silver, indium, iridium, gallium, copper, cobalt, nickel, tin, and ruthenium. However, this list is not exhaustive and care is always to be taken to investigate potential interference effects.

ISO 11495:2014 describes a method for the determination of palladium in palladium jewellery alloys, preferably within the range of fineness specified in ISO 9202, by means of inductively coupled plasma optical emission spectrometry (ICP-OES). The preferred palladium content of the alloys lies between 500 ? (parts per thousand) and 950 ? palladium. NOTE This method can be used to analyse other contents of palladium. This method is intended to be used as the recommended method for the determination of fineness in alloys covered by ISO 9202.

ISO 15093:2008 specifies an analytical procedure for the determination of either platinum in platinum jewellery alloys, gold in gold jewellery alloys or palladium in palladium jewellery alloys, with a nominal content of each precious metal of 999 ‰ (parts per thousand), by measuring specific elements listed in Tables A.1, A.2 and A.3.

ISO 11495:2008 describes a method for the determination of palladium in palladium jewellery alloys, preferably within the range of fineness specified in ISO 9202, by means of inductively coupled plasma (ICP) emission spectrometry. The preferred palladium content of the alloys lies between 500 ‰ (parts per thousand) and 950 ‰ palladium. Palladium jewellery alloys can contain silver, indium, gallium, copper, cobalt, nickel, tin and ruthenium. The presence of these alloying elements has not been observed to interfere with the determination method. If other elements are alloyed, a check is made as to whether any interference occurs.

ISO 15096:2008 specifies the analytical procedure for the determination of silver in silver jewellery alloys, with a nominal content of 999 ‰ (parts per thousand), by measuring specific elements listed in Table A.1.

ISO 11494:2008 describes a method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness specified in ISO 9202, by means of inductively coupled plasma (ICP) emission spectrometry. The preferred platinum content of the alloys lies between 850 ‰ (parts per thousand) and 950 ‰ platinum. Platinum jewellery alloys can contain silver, indium, gallium, copper, cobalt, nickel, tin and ruthenium. The presence of these alloying elements has not been observed to interfere with the determination method. If other elements are alloyed, a check is made as to whether any interference occurs.

Specifies a gravimetric method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness stated in ISO 9202. The procedure applies specifically to platinum alloys incorporating palladium, iridium, rhodium, copper, cobalt, gold, ruthenium, gallium, chromium, indium and less than 5 % tungsten. Some modifications are indicated where palladium, iridium, rhodium, gold or ruthenium are present.

Specifies a gravimetric method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness stated in ISO 9202. These alloys may contain palladium, iridium, rhodium, copper, cobalt, gold, ruthenium, gallium, chromium, indium and less than 5 % tungsten. Some modifications are indicated where palladium, iridium, rhodium, gold or ruthenium are present.

Specifies a gravimetric method for the determination of palladium in palladium jewellery alloys, preferably within the range of fineness stated in ISO 9202. These alloys may contain silver, indium, gallium, copper, cobalt, nickel, tin and ruthenium. Coprecipitated elements have to be determined by a suitable method and a correction applied.

The principle of the method specified is dissolving the sample in dilute nitric acid and determining the silver content of the resulting solution by titration with standard potassium bromide solution, using a potentiometric indication of the equivalence point. The alloys, preferably within the range of fineness stated in ISO 9202, may contain copper, zinc, cadmium and palladium. Apart from palladium, which must be precipitated before commencing titration, these elements do not interfere with this method of determination.