Bullion is defined as a mass of any one type of precious metals available today.  Precious metals are those metallic elements which are considered rare.  Commonly made of gold or silver, the value of bullion is calculated by the worth of the metal not the face value.  Mass and purity of the metal are the basis on which bullion is valued not the contrived face value.

While there have been improvements in the mining and refining processes of precious metals, new sources of ore have also been discovered.  The values of gold, silver and other precious metals may diminish based on these two factors.  The market value or level of demand also determine how metals are identified as precious.

Bulk ignots or coins are the two forms that commodity markets use to trade bullion.  Coins are minted by a countries government.  Australia, Austria, Canada, China, Mexico, Poland, South Africa, Switzerland, the United Kingdom, and the United States are 10 countries that mint gold and silver bullion coins.

The face values of bullion coins that are issued as legal tender are far below the actual commodity value of the metals.  Nominal face values are assigned to bullion coins upon minting of each coin.  For example, most gold coins issued by national governments with assigned currency values between 10 and 100 US dollars consist of no less than 31 grams of gold.  When the consistent rise in the price of gold per ounce is taken into consideration, the value of a piece of gold is about 12 US dollars per gram.  The currency value given to the gold bullion coin by the government has no meaning.

Following is a list of government issued gold and silver bullion coins:

1 Australian Gold Nugget, Lunar Series I and Lunar Series II

2. Austrian Philharmoniker

3. Canadian Maple Leaf

4. Chinese Gold Panda

5. Mexican Centenario, Libertand and Onza

6. Polish Orzel Bielik

7.  South African Krugerrand

8.  Swiss Vreneli

9.  British Britannia and Sovereign

10.  American Buffalo, American Eagle and Double Eagle

One of the largest bullion coins is the 10,000-dollar Australian Gold nugget.  This bullion coin, minted by the Australian government consists of 1 kilogram of 99.9% pure gold.  The Australian Gold Nugget is not the largest gold coin to have been minted by a national government.  The larger coins are not mass produced and they are not practical to handle.  The 100,000-euro Vienna Philharmonic, minted in 2004 and consisting of 31 kilograms of gold and the 1 million-dollar Canadian Maple Leaf, minted in 2007 and containing 100 kilograms of gold are two examples of the impracticality of the larger bullion coins.

Metal, purity and weight are the three factors that determine the value of bullion.  The metal used in each bullion coin is the main determining factor.   Silver is the least valuable precious metal with gold being right above silver and platinum being the most valuable of the three.  Because of their affordability, silver coins has risen in popularity with collectors today.