In a true fire assay a homogeneous sample of the material is taken and processed in the assay furnace to separate base metals from the precious metals.
After the sample passes through three separate furnace runs to prepare it, the sample is chemically separated to determine a weighed amount of Au, Ag, Pt, and Pd.
The final gold sample is weighed after the fire assay and parting process. This method continues to be better than any instrumentation analysis such as ICP or X-ray.
Our lab is built on a separate foundation to minimize vibrations. The final sample is weighed on the most accurate Swiss scale available.