I picked this up the other day at my LCS. The pin on the back dates it from 1850-1900. I am trying to figure out where it might be from? I was thinking the Alaskan gold rush but someone mentioned they think it may actually be from the California gold rush. Each would make sense as the miners would frequently turn raw nuggets into jewelry pieces like this. There is still some dirt and quartz on the nugget as seen in the pictures. It weighs 6.2 grams. The exact composition of it is 78.53% Au and 21.47% Ag. As far as I am concerned this is known as electrum. Any input is greatly appreciated!