Errata
On page 116 and 217 (in the Glossary) of Jewelry Savvy: What Every Jewelry Wearer Should Know, we state that the gram is a measurement for gold, and that 28.3495231 grams of gold is the equivalent of one ounce of gold.
That equivalent is incorrect. While 28.3495231 grams equal one ounce and sixteen ounces equal one pound for most purposes in the United States under what is known as the avoirdupois system, the jewelry industry uses a different measurement system called troy weight in calculating the weight of precious metals.
In both the avoirdupois and troy systems, the gram measurement is consistent, with one gram being the equivalent of 15.43 grains. However, one gram is equal to 0.035273962 avoirdupois ounces but only 0.032150747 troy ounces. Thus, one troy ounce is 1.0971 avoirdupois ounces, or almost 10 percent heavier than one avoirdupois ounce. However, under the troy weight system, there are twelve ounces to a pound, rather than 16 ounces to a pound. One troy pound equals 5,760 grains, while an avoirdupois pound equals 7,000 grains.
Accordingly, the text should be corrected to read: Gram is often used as a weight measurement for gold. 31.1034768 grams of gold equals one troy ounce of gold.
We sincerely regret the error.