Morris and Watson’s Analytical Services Department (Assay Laboratory) is an integral part of the business. Our mission is to determine the four major precious metals used in the jewellery industry which are Gold, Silver, Platinum and Palladium, contained in materials such as dore bars, alluvial gold, jewellery alloys and scraps and jewellery wastes called lemels and sweeps.
We accomplish this by using internationally accepted procedures of Fire Assay by fusion and cupellation together with Atomic Absorption Spectrometry and other wet chemical methods of analysis.
Equipped with one of the latest XRF machines, or X-Ray Fluorescence Technology, the Assay Laboratory is able to perform a pre-screening test and quick verification of unknown alloys and lemel samples submitted by customers for refining. This is critical for deciding the correct inquartation with fine silver, prior to actual fire assaying, a methodology which will ensure the best parting and/or separation of the sought-for-elements resulting in the accurate determination of the precious metals.
The analytical procedures developed and being used, have demonstrated the high standard of precision and accuracy that have given satisfaction to so many customers over so many years. Proof samples are analysed with every single batch of analysis to ensure corrections are applied if necessary. To add further confidence in the analysis, replicate samples are analysed, as well as internal check samples, within each batch of determinations.
More importantly, all analytical services are performed by professional and highly qualified Chemists and Chemical Engineers with more than 60 years of combined laboratory testing experience.
To render the most beneficial services to our paying (outside) customers, the Assay Laboratory works closely with other Departments as our internal customers. We assist the Chain Department in controlling the plating solutions’ quality and assaying all externally purchased gold and sterling findings.
Suspect caratage in gold and silver chains are verified and tested to ensure adherence to specifications. All gold and silver alloys granulated by the Vault and Fabrication sections, for use by the Casting department, are fire assayed to ensure compliance with internationally accepted fineness and specific requirements.
The largest of our internal customers is the Refinery Department with its well-structured sample receipt and handling and sample preparation procedures. The weighing, roasting and melting of the different types of materials for refining, follow time-tested sample preparation techniques to enable the extraction of a truly representative sample for analysis. Virtually all main and spent refinery process solutions are monitored by sampling and assaying.