Gold metal can be found in rivers, seas and land in many parts of the earth, but it is not easily extracted. Opening a mine is a time-consuming and costly operation and several tons of ore may are required in order to produce just one ounce of the precious metal. Therefore, despite its universal nature, gold remains a precious and rare commodity. In fact, it is estimated that only slightly more than 100,000 tons of gold have been taken from the earth during all of recorded history - an amount that could be contained in a 19-yard cube!