Precious Metals Gemology

Precious Metals Testing

Businesses involving buying, selling or processing refined gold, silver or platinum, find Bruker’s fast and accurate testing tools help run an efficient and profitable operation. Bruker’s precious metals testers can make sure that every penny is available out of every transaction.

Precious Metals Testing

Non-destructive Analysis of Valuable Objects and Jewelry Made of Gold, Platinum and Silver

X-ray Fluorescence (XRF) provides a non-destructive means for the testing of jewelry, cultural heritage and other valuable objects made from gold, platinum or silver. Portable XRF (pXRF), sometimes called a XRF “gun” or handheld XRF, provides compositional and purity analysis from any location. Desktop micro-XRF can provide layer analysis in detail. Explore below Bruker’s options for XRF analysis of precious metals by specialists, recyclers, refiners and bulk jewelry professionals.

Gold Karat Assay

Rapid Precious Metal Analysis by Portable XRF

The S1 TITAN and CTX are portable jewelry testers that provide accurate and repeatable karat hallmarking for gold jewelry. The karat is a measure of the purity of gold, with 24 karats being pure gold. Spelled carat in UK English, this fractional measure of gold is extremely important and has been adopted as an official measure in US law. For example, 18 karat gold is 18 parts gold and 6 parts another metal (18+6 = 24). Bruker's elemental analyzers convert the elemental percentages of gold into a karat measurement. 

Bruker gold jewelry testers provide gold concentration data and full alloy chemistry in as little as 2-5 seconds per sample, and testing is realized without any damage or alteration to the sample. Completely nondestructive analysis paired with accuracy within a few tenths of a percent of fire assay make testing gold jewelry easy for many businesses in the gold and industries. Some advantages of portable XRF for gold analysis are: 

  • with Rapid measurement times ranging from 2 to 15 seconds

  • On-screen results with output available in percent (%), karat (Kt) or PPM

  • Complete alloy composition from simultaneous multi-element analysis

  • Light-weight and easy-to-use instrument that does not require a highly-skilled operator

  • Fully downloadable results for record-keeping, report-generating, and trend analysis

Jewelry Layers and Coating

Jewelry Coatings and Layer Analysis with micro-XRF

Coatings are most commonly used for jewelry to improve aesthetics by coating a copper or silver jewelry with a layer of pure gold. M1 MISTRAL, micro-spot XRF is a fast and completely non-destructive method for quality control of decorative precious metal jewelry coatings. M1 MISTRAL can accurately analyze  gold, rhodium or palladium coating to ensure the correct thickness and coating composition. In addition to coating thickness analysis, M1 MISTRAL can also quickly test the composition and gold karat value of the jewelry and other precious metal items. 

Gold Coating is used to deposit a thin layer of pure gold onto the surface of another metal, which is most often copper or silver, by either chemical or electro-chemical plating. It is generally used on low-cost jewelry because it is inexpensive and easy to apply.  Thin gold plating lacks durability and can discolor if the jewelry is subject to only normal wear. Most gold plated jewelry is only one micron thick and can be easily analyzed with the M1 MISTRAL.  

Physical vapor deposition (PVD) is used to vaporize gold in a vacuum chamber and deposit it on the piece of jewelry.  When PVD is utilized with titanium nitride, a very hard material, it provides an extremely durable coating of gold, which is often used higher-priced jewelry – especially watches.   

Rhodium is another commonly used jewelry coating, it is silvery-white and very hard precious metal that is used to guard the surface against scratches. It also gives a nice reflective white appearance. It is most commonly used on white gold jewelry but it is used also for silver and other materials. 

Silver Analysis

Silver Analysis Made Easy with Portable XRF

The S1 TITAN and CTX provide portable and robust platforms for the analysis of silver. Pure silver (Ag), known as Fine Silver or 999.5 fineness, is much too soft to use in jewelry. However, it can be used in many other applications such as electrical components, bearings for jet engines, the formation of chemicals like formaldehyde and ethylene oxide and much more.  Typically, for jewelry, silver is alloyed with another metal such as copper (Cu) to provide strength.  Sterling Silver (Ag), the world standard for silver jewelry, contains 92.5% silver and usually 7.5% copper. Example applications for portable XRF include:  

  • Silver jewelry manufacturers can verify the purity of the silver they purchase to make jewelry as well as monitor their own process in alloying pure silver. 

  • Jewelry dealers can determine silver purity on the spot before they purchase coins, jewelry or “pure” silver 

  • Recyclers can identify silver content in electrical components, batteries and catalysts 

  • Museums can authenticate and provenance photographs based on silver content (as well as other elements) of the paper 

  • Silver content in artifacts can help determine provenance

Platinum Group Elements

Platinum group elements valuation with XRF

When buying, selling or recycling Platinum Group Metals (PGMs)—Platinum (Pt), Palladium (Pd) and Rhodium, it is important to be able to determine purity fast, effectively and reliably.  The Bruker S1 TITAN or CTX can provide the confidence and speed needed to make the most of the market today.  In mere seconds, the purity and value of platinum and other precious metals can be determined: 

  • Laboratory quality results from a compact, battery powered instrument  

  • No hazardous waste, chemicals, or consumables  

  • Accurate measurement of metal content where it matters, for example between 93% and 95% platinum 

  • Excellent correlation to lab results, without the high cost of sending samples to an outside lab 

  • Other important elements analyzed in addition to PGMs- Cerium (Ce), Lanthanum (La), Iron (Fe), Nickel (Ni), and Copper (Cu), Zinc (Zn), Zirconium (Zr), Barium (Ba), Osmium (Os), and Lead (Pb)