A gold bar is a quantity of refined metallic gold of any shape that is made by a bar producer meeting standard conditions of manufacture, labeling, and record keeping.

Larger gold bars that are produced by pouring the molten metal into molds are called ingots. Smaller bars may be manufactured by minting or stamping from appropriately rolled gold sheets.

The standard gold bar held as gold reserves by central banks and traded among bullion dealer is the 400-troy-ounce (12.4 kg or 438.9 ounces) Good Delivery gold bar.

The kilobar, which is to say 1000 grams in mass, is the bar that is more manageable and is used extensively for trading and investment. The premium on these bars when traded is very low over the spot value of the gold making it ideal for small transfers between banks and traders. Most kilobars are flat, although some investors, particularly in Europe, prefer the brick shape.^[1]

Types[link]

Gold bars are classified into two different types, cast and minted, based on their method of manufacturing.^[1] Cast bars are made by pouring molten gold into an ingot mold to shape the gold product. Minted bars are made from gold blanks that have been hand cut to the required dimensions from a flat piece of gold. Markings are almost always applied by presses.

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  1 oz diffractive kinebar

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  Imperial Chinese sycee

• 2oz gold Engelhard.JPG

  A 2oz 99.90% pure Engelhard poured gold bar

Standard bar weights[link]

Gold is measured in troy ounces, often simply referred to as ounce when the reference to gold is evident. One troy ounce is equivalent to 31.1034768 grams.

The much more commonly used avoirdupois ounce is used for measuring weights in most situation in daily life in countries using imperial measures, an avoirdupois ounce is lighter than a troy ounce; One avoirdupois ounce = 28.349523125 grams.

The standard gold bar held and traded internationally by central banks and bullion dealers is the Good Delivery bar with a 400 oz. nominal weight. However, its precise gold content is permitted to vary between 350 oz and 430 oz. 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.^[2]

• One tonne = 1000 kilograms = 32,150.746 troy ounces.
• One kilogram = 1000 grams = 32.15074656 troy ounces.
• One tola = 11.6638038 grams.
• One tael = 50 grams.^{[notes 1]}
• TT (Ten Tola) = 117 grams (3.75 oz)

Tola is a traditional Indian measure for the weight of gold and prevalent to this day. Many international gold manufacturers supply tola bars of 999.96 purity.

Largest gold bar[link]

The world's largest gold bar at the Toi gold mine.

The world's largest gold bar stands at 250 kg (551 lb), measuring 45.5 cm × 22.5 cm × 17 cm (equal to 17403.75 cm³, or 17.9 in x 8.9 in x 6.7 in≈1062.04 in³). It was manufactured by the Mitsubishi Materials Corporation, a subsidiary of Mitsubishi. It went on display at the Toi gold mine on July 11, 2005. It was valued in 2005 at 400 million yen (approximately $3,684,000 USD at the time^[3]),^[4][5] though at current 2011 gold prices it is worth approximately $15.3 million USD (value calculated is for gold weight alone @ $1,900/troy ounce, not accounting for the premium associated with being the world's largest gold bar).

Counterfeiting[link]

Gold bars are sometimes counterfeited. The first obstacle to convincing counterfeits is the exceptionally high density of gold; if the density is not similar, even manual inspection (picking up the bar) or rough weighing can reveal counterfeiting. Few metals are of similar or higher density to gold, and most are more expensive than gold (notably the platinum group), or similarly expensive, with two notable exceptions: depleted uranium and tungsten.^[6] Of these, depleted uranium is generally regulated as a nuclear byproduct, while tungsten is more readily available (and closer in density), and has found use in counterfeiting. This can be done either by coating a tungsten bar in gold,^[6][7][8] which has occurred since at least the 1980s,^[9] or taking an existing gold bar, drilling holes, and replacing the removed gold with tungsten rods.^[10]

While the densities of gold and tungsten are close, they are not exactly the same (tungsten is 0.36% less dense), so careful weighing (of standard-sized bars) or density testing will reveal these simple counterfeits, and other properties of gold and tungsten differ, but gold-plated tungsten will pass superficial tests.^[6] Well-established gold bullion dealers have been known to use various methods (including ultrasonic technology) to verify the integrity of their gold bars.

Gold-plated tungsten bars (as well as pieces of jewelry) are available commercially from China (the main source of tungsten), primarily intended as inexpensive but impressive gifts.^[11]

See also[link]

• Precious metal
• Fort Knox Bullion Depository
• Gold as an investment
• Gold coin
• Millesimal fineness
• Official gold reserves
• Doré bar
• Bullion
• Ingot
• ChipGold

Notes[link]

References[link]

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