They are called Maple Leafs.
maple leaf
A copy of Canada's gold maple leaf coin in the royal Canadian mint in Ottawa with a face value of 100,000,0 Canadian dollars.
It's a gold bullion coin issued by South Africa, similar to the American Eagle or Canadian Maple Leaf coins. They're sold for their gold content, not for spending.
The value of a Gold Maple Leaf varies depending on multiple factors, including the gold content, year, mintage and condition. Check out the Gold Maple Leaf page at APMEX.com for more about the coin itself and to gauge pricing. APMEX - The Gold Standard in Precious Metal Trading
A Canadian $20.00 gold coin is worth around $400.00
American Eagle Gold Bullion Coins, also called simply Gold Eagles, have been issued by the US mint since 1985 and are popular with collectors and investors. They are guaranteed by the US government. According to the Mint, they can be purchased at almost any coin or precious metal dealers, and from selected banks and brokerage houses. Proofs may be purchased directly from the Mint's website.
More information is needed. If it's a bullion piece it'll have its gold weight somewhere in the design, so it'll be worth at least as much as that amount of gold. If it's a $1 coin with a swimming loon on one side above the date, it's not gold. Like its less-used American counterpart the coin is made of base metal and is only worth a buck. The gold color is actually a brass alloy.
No.
When buying gold, it is measured in ounces. There are 31.103 grams in each ounce of gold. A 1 oz gold coin would therefore weigh 31.103 grams which is different from the regular conversion of grams to ounces.
4.00 dollars
The Louisiana Purchase Exposition gold coin weighed 1.672 grams and consisted of 90% gold and 10% copper. This means there is 1.5048 grams of gold in the coin or 0.04837 troy ounces.