Gold and silver are the most well-known examples of precious metals. The others are platinum, rhodium, iridium and osmium. What makes a metal precious? It needs to be an element that occurs naturally and is either extremely uncommon or very highly sought-after. The term “mass fraction,” which refers to the number of grams that are expected to be present in a ton of earth crust, is the most effective way to describe the scarcity of an element.
You could find:
0.004 grams of gold in 1 ton of crustal earth
0.005 grams of platinum in 1 ton of crustal earth
0.075 grams of silver in 1 ton of crustal earth
0.0015 grams of osmium in 1 ton of crustal earth
0.0002 grams of rhodium in 1 ton of crustal earth
60 grams of copper in 1 ton of crustal earth
84 grams of nickel in 1 ton of crustal earth
About 50,000 grams of iron in 1 ton of crustal earth
According to estimates, the whole earth’s crust is around 2.6 x 1022 kg, which indicates that there are approximately 14 trillion ounces of gold dispersed all across the whole world. This would also mean the total supply of silver is around 262 trillion ounces. In the course of human history, we have extracted almost 49 billion ounces of silver. But wait, does this mean there’s still more than 70% of unmined silver hiding beneath the earth? Why not just mine for more of it, since silver is so useful in heavy industries?
For starters, a significant portion of the crust’s silver will never be accessible. The cost of operating a silver mine is also very high, making it difficult to mine more silver. The cost of mining and processing one ounce of gold is roughly a few hundred dollars. Meanwhile, the cost required to mine one ounce of silver is roughly equivalent to the cost of mining one ounce of gold. Silver is far too expensive to mine economically at its current price of about $20 per ounce. In case you wonder how they mined silver cost-effectively, well, silver is typically extracted alongside other metals.