System of measurement The same is true of quarts, gallons, etc. Six US gallons are a little less than five imperial gallons. The Avoirdupois system served as the general system of mass and weight. In addition to this there are the Troy and the Apothecaries' systems. Troy weight was customarily used for precious metals, black powder and gemstones. The troy ounce is the only unit of the system in current use; it is used for precious metals. Although the troy ounce is larger than its Avoirdupois equivalent, the pound is smaller. The obsolete troy pound was divided into 12 ounces, rather than the
Gold IRA Savings Plan (TSP), and 401(k)s. The four precious metals allowed to be held in an individual retirement account are gold, silver, platinum and palladium, provided they are in the form of IRS-approved coin or bar products. Since gold is the most commonly purchased of the four, the overarching term "gold IRA" is used most often as industry slang to mean a retirement account containing any combination of precious metals. Other terms such as, "precious metals IRA", "silver IRA", "platinum IRA", or "palladium IRA" are also frequently used. Investors often use precious metals as a long-term hedge against inflation, to diversify