Spending a few hours digging for semiprecious stones can be a fun family activity for a day trip or a vaction. You'll have to pay the cost for permits and entrance fees, as well as fees for buckets of ore or other materials, but you keep what you find. Many locations in the United States allow you to practice prospecting.
Source: Where Can You Dig for Semiprecious Stones? | eHow.com http://www.ehow.com/way_5304971_can-dig-semiprecious-stones.html#ixzz1Qn9fcMz2