Gold bar

A minted bar (left) and a cast bar (right)

Based upon how they are manufactured, gold bars are categorized as having been cast or minted, with both differing in their appearance and price. Cast bars are created in a similar method to that of ingots, whereby molten gold is poured into a bar-shaped mold and left to solidify. This process often leads to malformed bars with uneven surfaces which, although imperfect, make each bar unique and easier to identify. Cast bars are also cheaper than minted bars, because they are quicker to produce and require less handling.

Minted bars are made from gold blanks that have been cut to a required dimension from a flat piece of gold. These are identified by having smooth and even surfaces.

To prevent bars from being counterfeited or stolen, manufacturers have developed ways to verify genuine bars, with the most common way being to brand bars with registered serial numbers or providing a certificate of authenticity. In a recent trend, many refineries would stamp serial numbers even on the smallest bars, and the number on the bar should match the number on its accompanying certificate.[3]

In contrast to cast bars (which are often handled directly), minted bars are generally sealed in protective packaging or tamper-evident technology to prevent tampering and keep them from becoming damaged. A hologram security feature known as a Kinegram can also be embossed directly on a gold bar. Bars that contain these are called Kinebars.[4]

• 
  1 oz diffractive kinebar
• 
  Bar in protective casing

Gold prices (US$ per troy ounce), in nominal US$ and inflation adjusted US$ from 1914 onward

Gold is measured in troy ounces, often simply referred to as ounces when the reference to gold is evident. One troy ounce is equivalent to 31.1034768 grams. The troy ounce is heavier than the avoirdupois ounce, a commonly used unit for measuring weight in the United States customary system. One avoirdupois ounce equals 28.349523125 grams.[5]

The standard gold bar held and traded internationally by central banks and bullion dealers is the Good Delivery bar with a 400 ozt (12.4 kg; 27.4 lb) nominal weight. However, its precise gold content is permitted to vary between 350 ozt (10.9 kg; 24.0 lb) and 430 ozt (13.4 kg; 29.5 lb). The minimum purity required is 99.5% gold. These bars must be stored in recognized and secure gold bullion vaults to maintain their quality status of Good Delivery. The recorded provenance of this bar assures integrity and maximum resale value.[6]

• One tonne = 1,000 kilograms = 32,150.746 troy ounces.
• One kilogram = 1,000 grams = 32.15074656 troy ounces.
• One tola = 11.6638038 grams = 0.375 troy ounces.
• One tael = 50 grams.[notes 1]

The world's largest gold bar at the Toi Gold Museum.

The world's largest gold bar stands at 250 kg (8,038 ozt), measuring at the base 455 mm × 225 mm (17.9 in × 8.9 in) and 170 mm (6.7 in) high with 5 degree draft angle (equal to 15,730 cm³ or 960 cu in). It was manufactured by the Mitsubishi Materials Corporation, a subsidiary of Mitsubishi. It went on display at the Toi Gold Museum on 11 July 2005. Its gold content was valued in 2005 at 400 million yen (approximately US$3,684,000 at the time).[21][22][23] As of January 2023, it is worth approximately US$15.1 million.[24]

• Media related to Gold ingots at Wikimedia Commons