When investing in gold, silver, or platinum, precision is everything. Yet, a common stumbling block is the unit of measurement itself. When a price is quoted "per ounce," it refers to the Troy Ounce, a standard that differs significantly from the imperial ounce used in a grocery store.
The Crucial Distinction
Troy Ounce (ozt)
≈ 31.10 grams
The global standard for precious metals.
Avoirdupois Ounce (oz)
≈ 28.35 grams
The standard "kitchen" ounce.
Why the Industry Sticks to Troy
The troy system likely originated in Troyes, France, during the Middle Ages. While the world moved to metric, the bullion market retained the troy ounce to ensure seamless cross-border trading.
It serves as an international language of value; a gold coin purchased in New York holds the exact weight standard as one sold in London or Hong Kong.
Know What You Own
Understanding the troy ounce ensures you know exactly what you are buying and how it is valued.