Wednesday , 6 December 2023

A “Troy” Ounce of Gold is 10% Greater Than a Regular Ounce – True or False? (+4K Views)

When the price of gold is mentioned as costing “x dollars per troy ounce” do you fully appreciate the significance of the term “troy”? When looking to buy gold jewellery do you fully understand what the difference is between an item that is 10 “karat” gold and another item stamped 18 “karat” gold (other than that it is much more expensive)? Let me explain. Words: 587

This article was written by Lorimer Wilson, editor of and the FREE Intelligence Report newsletter (see sample here). You can also Follow the munKNEEdaily posts via Twitter or Facebook. Please note that this paragraph must be included in any article re-posting to avoid copyright infringement.

Wilson goes on to say:

Definition of “Karat”

The term “karat” (kt) is used to describe the unit of measurement for the proportion of gold (i.e. % purity of the gold content) in a piece of jewellery, coin, ingot or bar as per the table below.

Gold will often be mixed with “filler metals” such as silver, palladium, platinum, nickel and even copper to combat the softness of pure 24 karat.

  • Gold which contains a degree of silver, platinum or palladium is referred to as ”white gold” and will classify with a higher amount of karats while the presence of nickel leads to a slightly lower designation of karats.
  • Copper is used to give gold durability and give it a golden rosy tone.

Below is a table outlining the karat designations at various gold purity levels plus the extent of ”fineness” as is used in some countries such as Italy.

Karat/Fineness Gold Content [Purity]
24 karat 99+%
22 karat/917 91.6%
21 karat 87.5%
20 karat 83.3%
18 karat/750 75.0%
15 karat 62.5%
14 karat/583 58.5%
10 karat/417 41.7%
9 karat 37.5%
8 karat 33.3%
1 karat 4.2%

In some countries “karat” and “carat” are used interchangeably although, strictly speaking, the word’s correct meaning is as defined above.

All jewellery is required by law to be stamped so consumers will know the quality of gold used. Jewellery (Canadian and British spelling) made in North America is typically marked with the karat grade (10K, 14K, etc.), and jewelry (U.S. spelling) made in Italy is typically marked with the “fineness” such as (417, 583, etc.). Most retail gold items have a karat rating in the range of 9 to 18. In the U.S. the minimum karat value for an item to be sold as gold jewelry is 10. In the UK 9 karat is more common.

The number 24 may have originally been chosen to represent pure gold because it divides evenly by 2,3,4,6 8 and 12 and, therefore, it is easy to talk about a gold item being half pure (i.e.12 kt), two-thirds pure (i.e. 16kt) etc. Nine karat would thus be three-eighths gold, 18 karat would be six-eighths (i.e. three quarters).

Definition of a ”Troy” Ounce

The term troy ounce (ozt) is a unit of imperial measure most commonly used to gauge the weight, and therefore the price, of precious metals. One troy ounce is equivalent to 1.09714 avoirdupois (our conventional every day measurement) ounces i.e. a troy ounce is 9.714% greater in weight than the regular measure and 1 kg. consists of 32.1507466 ozt.

100% pure gold is defined as having a purity of 24 karats so if something is 24 karat gold then it’s made of gold and nothing else – regardless of size. Gold is a relatively soft metal and high-karat gold tends to be easily damaged and, as such, a 24 karat item is usually reserved for display or ceremonial use as the picture of me with “my” 100kg. Canadian Maple Leaf 99.99999% pure gold coin which is now worth in excess of $5,144,000 USD! (100kg. x 32.1507466 troy oz. x $1,600/ozt. USD)

World's First 100-kg, .99999% Pure Gold Bullion Coin Editor-in-Chief Lorimer Wilson with the world’s first 100-kg, 99999 pure gold bullion coin with a $1 million face value. It was produced by The Royal Canadian Mint.


Please keep the distinction between ounces and troy ounces in mind when buying small quantities of gold and/or silver and number of karats when buying gold jewellery.

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One comment

  1. I thought that Gold also had Helium in it and that was the reason that it was going up…