According to the latest available research, there are currently about 1 billion ounces of silver sitting above ground on the entire planet earth. And gold? How about 5.5 billion ounces. Yep, that's right.
Now in terms of "gold-in-the-ground" vs. "silver-in-the-ground," gold is indeed rarer by a factor of about 8:1. Each year, it is estimated that approximately 800 million ounces of silver is mined compared to 100 million ounces of gold. Then, once you take into account silver recycling (jewelry, silverware, etc), the total annual supply of silver is in the neighborhood of 1 billion ounces.
What makes silver special, and therefore much rarer, is its value as an industrial metal. According to Kelly Mitchell, author of Gold Wars | The Battle for the Global Economy, "Silver is the most useful industrial metal ever found. Obviously, far greater quantities of iron and copper are used, but silver enjoys more varied applications due to its properties. More important, these applications use only trace amounts of silver, so there is no question of recuperation by tapping large concentrations. The amount used by industry - electronics, solar power, mirrors, health care (antibacterial), lasers, even clothing - exceeds annual mine production."
Another point of view comes from silver analyst Ted Butler of Butler Research. He asserts that, "Simply put, so much new silver mine production is already earmarked and spoken for by industrial consumption and other fabrication needs, that only a small percentage (10%) of current silver mine production is available for investment."
Whiles Messrs. Mitchell and Butler have slightly different numbers, the conclusion remains the same. Once industrial demand is satisfied, there is very little silver remaining for investment. The world needs to keep annual mine output at 800 million ounces or more just to keep up with industrial demand.
So to wrap this up, 100 million ounces of gold are pulled out of the ground each year - effectively all of which is available for investment. After taking into account industrial demand, there are approximately 100 million ounces annually of silver available for investment. You don't have to be Stephen Hawking to see that 100 million ounces = 100 million ounces. And yet gold is 63 times more expensive than silver - something which makes absolutely no sense on a fundamental basis. I understand there are reasons why gold will probably always be worth more than silver, but 63 times more?