Gold and silver aren't stable, they fluctuate all the time just at long timescales compared to humans. When the Comstock Lode was discovered it massively affect

Gold and silver aren't stable, they fluctuate all the time just at long timescales compared to humans. When the Comstock Lode was discovered it massively affected the price of silver. Similarly when Spain stole Aztec gold it caused changes in the value of gold. If someone ever manages to mine asteroids for gold or we discover a previously unknown reserve we'll see more price shocks. I don't know where you got the idea that the supply of gold was stable; it is merely inflexible because it depends on physically digging it out of the dirt.