As we teach in our Safety Step course, there are very few things in this day and age that are still measured in Troy Ounces. The first two that always come to my mind are precious metals and gun powder. The reason these things are still measured in Troy Ounces rather than the “regular” (or Avoirdupois) Ounce that we use for pretty much everything else, is because the Troy Ounce is a more precise measurement.
The Troy Ounce is a measure that dates back to the middle ages, and it is heavier than the avoirdupois ounce by approximately 10%; the conversion is as follows:
1 troy ounce = 1.09714286 avoirdupois ounces
The Troy Ounce is believed to have originated in a French town called Troyes in the Middle Ages. Traveling merchants from around the globe would buy and sell goods in France’s trade markets, which made it a necessity to incorporate a standardized weight system that would make trading and doing business a lot easier for every country.
King Henry II of England adopted the Troy Weight system, which was widely used in Britain’s coinage system in the 1400s. In the early 1500s, the Troy Ounce was accepted as the official standard of measure for gold and silver in Britain, with the U.S. adopting this measurement method as well in 1828, as the U.S. Mint expanded our coinage system.
Just as traders did centuries ago, investors all over the world today still benefit from this unit of measurement. As mentioned previously, because the Troy weight system is so precise, it makes it easy for bot sovereign and private mints to consistently produce the purest precious metals investments in the world.
It’s not uncommon for dealers (or anyone who has access to a smelting kit) all over the world to try and rip off customers by selling a regular ounce of a metal at the current Troy Ounce price, which would of course cheat the investor out of getting the amount of metal he/she paid for.
A 10 percent difference in weight might not seem like much in small quantities, but it begins to add up quickly as you start buying in bulk, and accumulating metals throughout the years. A good way to choose where you buy your metals is to ensure the description lists the item’s weight in Troy Ounces, as opposed to just ounces. However, it’s worth noting that the standard for copper is to be weighed in avoirdupois ounces because it’s a base metal with many commercial uses.