By the end of the Civil War the greenbacks had lost a small amount of their value, while Confederate money was worthless. Most historians agree that the economies of the North and of the South were the deciding factors in the victory for the North. Virginia City, Montana gold played the winning part in the Civil War. Over millions of years, the mountains behind and above Virginia City, Montana were eroded away by glacial and stream action. The process of erosion drew off the lighter rock material and left the gold in the form of gravel.
Placer mining is the separation of pieces of gold from the pieces of stone in the gravel.
Some of the nuggets that are found here were originally part of the bedrock, broken loose into boulders and rocks. A rock might contain microscopic gold, gold you can't see. But it's like chewing gum. As the rock is bashed and bruised by the streams and glaciers, the gold clumps up and the sand falls loose. Gradually a nugget of gold develops, concentrated by nature as it sticks to itself.