How does this work? You buy an empty bag and then fill it with what you find? Do they "salt" the slurry or are these coming directly from the mine?

It's a bag of either gems or fossils that are mixed with sand and dirt. Dump a small portion at a time, into the sifter and use the running water in the canal to wash away the debris, revealing the gems or fossils.

They also have bags and information cards for thier stones inside. They are priced fairly, and have a great selection.

What RJ said, then keep what you found in your bag.