Unlike the ounces you find in grocery stores, a troy ounce is a unit that is commonly used for precious metals like silver bullion.
Although their names might not indicate this, these two units are not the same in weight.
While 1 troy ounce (troy oz) of silver is equal to 31.1034768 grams, 1 imperial ounce will equal only 28.3495 grams.
The differential of close to 10% makes it absolutely vital for precious metals buyers and sellers to be aware of the differences between these two units (imperial ounce vs troy ounce).
History of the Avoirdupois Ounce (the grocery store ounce)
This unit is commonly used throughout the USA and is also known as an imperial ounce. The word ‘avoirdupois’ is derived from its Middle-English ancestor – “Avoir de pois.” This means “goods sold by weight.”
An Avoirdupois Ounce is denoted by the symbol “oz.” and equals 28.3495 grams.
The first use of this unit dates back to the early 13th century. It was then updated and made official almost six centuries later. In 1959, the unit was standardized and defined by the countries that agreed to use this unit.
Although many countries have now begun moving away from this system, drawn to the simplicity and widespread use of the metric system, the United States remains loyal to Avoirdupois Pound standard of weights even today.
History of the Troy Ounce
From the beginning, troy ounces have been tied to measuring the weights of precious metals. And every quest to uncover its origin seems to lead researchers towards a trade market in a town called Troyes, in France.
In the 1400s, King Henry II adopted this system of weights as an official standard of measure for gold and silver in Britain. The United States followed suit in 1828. Since then, it has remained one of the most-used weighing system for precious metals. However, some mints like the Chinese Mint, have started switching to the metric system for the sake of standardizing weights.
A troy ounce is denoted by the symbol “troy oz.” or sometimes "ozt" and equals 31.1034768 grams.
This entire concept may be a bit confusting as all US Bullion Dealers market and advertise gold bullion and silver bullion by the ounce. However, they are actually dealing in troy ounces. For the sake of convenience and simplicity, it has become a US industry standard to refer to troy ounces as simply ounces. But now you know the technical difference.
How many grams in an ounce of Silver?
First and foremost, the world most often measures silver bullion using either troy ounces or grams.
1 troy ounce has precisely 31.1034768 grams of fine silver.
For this real world example, we will use a two decimal point, $12 dollar digital scale to weigh some common 1 troy ounce silver bullion products.
To begin we will weigh how many grams are in this 1 oz SD Bullion Silver Freedom Round made with .999 fine silver bullion.
Up next we will weight the world's most popular silver bullion coin by sales volume, the 1 oz American Silver Eagle coin, also comprised of .999 fine silver bullion.
Note that it is common for both government and private silver mint products to error on the heavy side, by containing an extra tenth or more of silver grams per item.
It is very unlikely you will ever find genuine silver bullion products which do not contain a minimum of the troy ounce silver weight explicitly stamped upon them.
For a deeper dive on how you can authenticate your silver coin, silver bar, and silver round's authenticity... check out our video on how to perform non destructive, cost effective Specific Gravity tests on bullion products at home.
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