Fire assays are the standard for valuing gold and silver at major mining companies and refineries. In the process, metal is melted down, then the precious metal sample is chemically separated from the other metals. The process is different for each precious metal, using a variety of chemicals during the separation process.
To perform a fire assay, a sample is melted and mixed with lead oxide as well as a few control chemicals. The lead in the mixture binds with the precious metal in the sample. The entire mixture is then poured into a mold and cooled.
Because the lead is so dense, it sinks to the bottom of the mold, where it is chipped off and placed into a cupel and melted again. The cupel absorbs the lead, leaving only precious metal behind. The precious metal is then measured against the size of the rest of the sample to determine its overall purity.
A fire assay—or melt test—is the most accurate precious metal assay. In fact, it’s accurate between one part per thousand and one part per ten-thousand. We recommend the fire assay process, because it is the most accurate and the best way to determine the amount and purity of precious metals.
Manhattan Gold & Silver is the ONLY refiner I will sell my metals too. If there is a piece that is in the 14K that tests 18K they will point it out to you and pay accordingly! I can’t say the same for the other “dealers” on 47th street! Whether it’s buying bullion for clients or melting scrap you know you are always getting the best price! They take the “game” out of doing business.