At least 55 different categories for gold bullion bars trade globally, according to research conducted by Grendon International Research in Australia.

The most common bars encountered are the London Good Delivery 400-ounce bar and the COMEX Good Delivery 100-ounce bar, both of which are at least 99.5 percent pure gold.

The LGD bar, according to Grendon International Research, is the standard bar used in transactions on the London Bullion Market. The weight is not stamped on each bar and the weight can vary between 350 and 430 troy ounces.

Connect with Coin World:  

• Sign up for our free eNewsletter
• Like us on Facebook  
• Follow us on Twitter

The CGD bar is the standard bar used in transactions on the COMEX Division of the New York Stock Exchange. The weight of each varies between 95 and 105 troy ounces.

Another bar that seems to be generating considerable worldwide interest, according to metals market analysts, is the doré bar.

A doré bar a semi-pure alloy of gold and silver, usually created at the site of a mine. It is then transported to a refinery for further purification. The proportions of silver and gold can vary widely, but is usually at least .800 fine gold. Doré bars weigh as much as 25 kilograms.

More from CoinWorld.com:

Sunshine Minting operating around the clock to meet silver demand

Stamps in Presidential Coin & Chronicles sets from secondary market

Canada honors wreck of SS Edmund Fitzgerald with coin

Selling silver to eventually melt not always wisest option

Silver bullion coins on allocation at major national mints