A gold ingot is a method of storing gold in bulk for currency reserve purposes or further processing into gold jewelry, gold charms, and other ornamental uses. Ingots are usually a rectangular, molded brick-like shape with some sort of imprint on the surface indicating the purity and net weight of the gold, as well as potential ownership information. Another common name for a gold ingot is a gold bar, though ingots are a special subsection of the definition of a gold bar.
Gold bars are usually small, hand-held quantities of gold weighing one ounce or more, and are cut or stamped from a rolled sheet of the metal. The gold ingots that are held as gold reserves by national central banks are much larger. Standard accepted size for a gold ingot among bullion dealers is 400 troy ounces (12.4 kg). The Roman monetary system initially established the measure of a troy ounce while using bronze bars as their currency, and it is equal to one-twelfth of a pound, or 480 grains (31.1 grams). While the avoirdupois ounce is used as a standard of measure in cases other than that of precious metals, it is equal to one-sixteenth of a pound (28.35 grams).
Ingots of gold can be quite heavy, therefore, despite the fact that they don’t appear to be very large, measuring 6 inches by 3 inches by 2 inches (36 cubic inches or 589 cubic centimeters). A gold ingot weighs approximately 27 pounds (12.25 kilograms). The official name for the gold ingot that is held by central banks is the “Good Delivery” bar, and their actual weight is allowed to vary between 350-430 troy ounces (10.9-13.4 kilograms). Minimum purity of the gold ingot must be at least 99.5% gold. Good Delivery is also the official name and size designation for silver ingots and other precious metals held as currency reserves.
It is estimated that the world’s central banks hold 19% of all existing gold as currency reserves. Nations from the United States to Burundi, over 110 in total, have reported their gold reserves to the International Monetary Fund. This is all stored in the form of the gold ingot, though actual quantities are not verifiable, as most central banks do not allow foreign access to their reserves.
Occasionally, larger-than-standard gold ingots will be minted for various reasons. The largest gold bar on record was produced by Mitsubishi Corporation at its Toi Gold mine in 2005. The 18-inch long bar (45.72 centimeters) weighs 551 pounds (250 kg) and was valued at 400 million yen, at the time. In 2005, that was equivalent to approximately $3.7 million US Dollars (USD).