Understanding Gold Purity

Gold Purity Terminology

The measure of purity, or fineness, of gold simply means finding out the gold-to-metal additive ratio.

You may have previously thought that gold is gold, but the fact of the matter is not all gold is created equal! Some pieces of gold will contain more actual gold than others, and some pieces will have more additive metals than others. Before I delve into the nitty gritty on gold, let’s take a look at a few terms that you may come across when studying about or shopping for gold:

  • Assay: A test which determines metal content and quality.

  • Bullion: Precious metals in a bulk, uncoined form such as gold bars, considered in mass rather than value.

  • Carat: Not to be confused with Karat in North America, a Carat is a unit of measurement used for precious stones. Equal to 200 milligrams. Outside of North America, Carat is used in the same context as Karat.

  • Ductile/Ductility: How capable a metal is to being deformed using tensile force. Ex. Ductile materials can be stretched into thin wires without fracture.

  • Hallmark: A symbol or mark stamped on a piece of precious metal which certifies its standard of purity.

  • Karat: Unit of measurement for fineness of gold, with the higher numbers containing more gold and 24K being the finest.

  • Malleable/Malleability: How capable a metal is of being deformed using compressive force. Ex. Malleable metals can be hammered or rolled into thin sheets.

  • Millesimal Fineness: A system used to show the purity of precious metals by parts per thousand rather than karats.

  • Troy Ounce: 31.1034768 grams, or approximately 1.09714 standard “avoirdupois” ounces.

  • Troy Weight: A system of measurement used for gemstones and precious metals, where a full Troy Pound consists of 12 “troy” ounces rather than the 16 “avoirdupois“ ounces in a standard pound.