The size of the monetary base is determined by the amount of gold that is presented to the Treasury (or private banks) to be minted into gold coins.

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They will be minted in gold, silver, bronze and base metals.

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Gold coins are often minted in smaller sizes (one ounce or less), making them a more convenient way to invest in gold than the larger bars.

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Mr Mugabe was presented with a cake said to weigh 89kg (196lb), and gold coins were minted to mark the occasion.

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As a result few gold coins were actually minted and the vast majority of US currency was silver.

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