How Many 90% Silver Half Dollars Make an Ounce?
Understand the precise calculation for converting 90% silver half dollars into a standard troy ounce of pure silver.
The U.S. Mint historically produced coinage containing a significant amount of silver, with 90% silver half dollars being a notable example. These coins, minted primarily before 1965, hold appeal for both collectors and investors. Their intrinsic value, derived from their precious metal content, often surpasses their face value, making them a tangible asset.
Understanding 90% Silver Half Dollars
The term “90% silver” indicates that these half dollars are composed of 90% pure silver and 10% copper. The copper alloy was included to provide durability, as pure silver is a relatively soft metal that would wear down quickly in circulation. These coins, which include designs such as the Walking Liberty, Franklin, and the 1964 Kennedy half dollars, were standard circulating currency for decades.
A standard 90% silver half dollar has a gross weight of 12.5 grams. This gross weight includes both the silver and copper content. The pure silver content is thus a fraction of the coin’s total weight. Precious metals like silver are typically measured using the troy ounce, a unit of mass distinct from the more common avoirdupois ounce used for everyday goods.
One troy ounce is precisely equivalent to 31.1034768 grams. This specific measurement standard is used globally in the precious metals market to ensure consistent valuation and trading. In contrast, an avoirdupois ounce is approximately 28.35 grams, highlighting the importance of using the correct unit when dealing with silver.
Calculating Pure Silver Content Per Coin
Determining the pure silver content in a single 90% silver half dollar involves a straightforward calculation based on its gross weight and purity. Since the coin weighs 12.5 grams and is 90% silver, the calculation is 12.5 grams multiplied by 0.90. This yields 11.25 grams of pure silver per coin.
To express this in troy ounces, the pure silver weight in grams is divided by the number of grams in one troy ounce. Using 31.1034768 grams per troy ounce, 11.25 grams divided by 31.1034768 grams/troy ounce equals approximately 0.36169 troy ounces. Therefore, each 90% silver half dollar contains about 0.36169 troy ounces of pure silver.
Determining Quantity for One Troy Ounce
To determine how many 90% silver half dollars are needed to accumulate one troy ounce of pure silver, the total grams in a troy ounce are divided by the pure silver content per coin in grams. One troy ounce contains 31.1034768 grams of pure silver. Each 90% silver half dollar contains 11.25 grams of pure silver.
Dividing 31.1034768 grams by 11.25 grams per coin results in approximately 2.76475 coins. This means that three 90% silver half dollars are required to obtain at least one full troy ounce of pure silver. For example, two coins would contain 22.5 grams of pure silver (0.723 troy ounces), falling short of one troy ounce. Adding a third coin brings the total pure silver content to 33.75 grams (1.085 troy ounces), which exceeds the one troy ounce target.
This calculation focuses solely on the pure silver content, not the overall physical weight of the coins. The copper alloy, which makes up 10% of the coin’s total weight, is not considered in this specific determination of silver ounces. For tax purposes, these coins are generally treated as collectibles, and any gains from their sale may be subject to capital gains tax rates applicable to collectibles, which can differ from standard long-term capital gains rates. This intrinsic value of the silver is the primary driver for investors seeking to hold physical precious metals.