Items you will need
- gram scale
- table of weights and measures
The value of gold cannot be determined without knowing its purity and weight. Gold's purity is valued in carats and its weight is measured in grams or Troy Ounces. Unless it's scrap gold that is being weighed, the gold content will probably be stamped on the item, certifying it to a certain standard of purity; such as 12 carats which is 50% pure; or 99.99% fine, which is equivalent to 24 carats, 100% pure gold. Digital gram scales and chemical gold content testing kits can be purchased on the internet for under $30.
Calibrate the scale by testing it with an object of known weight. For example, a 50 gram weight can be bought along with the scale. Set the device on a hard, level surface and place the known weight in the center of the scale tray. The reading should coincide exactly with the test weight. Now, set the gold item on the scale and read the result. Unless the purity of each gold item is known, weigh each item separately.
List each piece and its exact weight on a sheet of paper together with its gold content percentage. Daily spot gold prices can be found in newspapers, through phoning a gold bullion dealer, or on the internet. Prices for precious metals like gold, platinum and silver are quoted in Troy Ounces.
View a weights and measures table in a Webster's dictionary or see the References section. Let's say you want to sell an 18 carat gold place setting that weighs 15.5 grams. If pure gold is 24 carats, 18 carat gold is only 18/24 as pure or 3/4 (75%) the gold content of pure.
Note that the weight table shows 1 Troy Ounce weighing about 31 grams. With the price of gold around $1,400 per ounce, the gold value of the place setting is calculated as, $1,400/31 X 15.5 X .75 = $525. Remember, the weight of the object doesn't tell you the weight of the gold content. That's why you must adjust each item's weight by the purity percentage to determine its value.
Be advised that calculating the intrinsic value of gold alone might greatly undervalue historical gold coins or other gold items that possess numismatic or collectors value. Such pieces should be valued by a certified appraiser. In addition, where gold content is not known, laymen should defer to the expertise of a reputable jeweler.