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Ask MGS: Refinery Lingo

If you are new to selling your precious metal scraps to a refinery like MGS, you may be surprised to discover some new lingo come up during the transaction phase. Since we’re a full-service refinery, we have capabilities and tools that you won’t find at the average “Cash 4 Gold” shop. Below are explanations for some of the lingo you’re likely to hear in our shop.


Short for x-ray fluorescence, this assay measures the amount of pure precious metal in a sample with an accuracy of 2-5 parts per thousand (ppt). The X-RF machine (pictured) bathes the sample in x-rays, causing the sample to emit light (fluorescence) at an energy level specific to its atomic structure. In less than 10 minutes, the machine analyzes this energy level to determine the amounts of precious metals within the sample. We operate two X-RF machines so can quickly serve multiple clients.

Sweeps (AKA: polishing sweeps, bench sweeps, polishing dust)

Sweeps refers to the dust collected from a jewelers work area. While sweeps are mostly wax, buffing wheel fibers, jewelers rouge, buffing compound, dirt, and other waste materials, it also contains precious metals that we can extract for our clients.

Millesimal fineness (“nines fine”)

Similar to using karats to indicate gold purity, millesimal fineness denotes the precious metal in an alloy by ppt. For example, a gold coin stamped 750 would mean it is 75% pure gold (18-karat). The term “nines fine” is a colloquial expression of millesimal fineness. Gold stamped 900, or 90%, is referred to as one-nine fine. Gold that is 99.9% pure, or 999, is three-nines fine.

In our next post, we’ll go over some of the unique tools and terminology we use in the refinery – where the magic happens.

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