This fee pay mine is open 7 days a week all year (weather permitting) from 8am to 5pm.  They accept cash only.  You can sift through dirt that you dig for rubies and sapphires.  You can look for more details at their website:

http://www.masonsrubyandsapphiremine.com/

Here are the directions from the website:

From Franklin proceed north on St. Road 28 for about 4 miles, which at that point there will be a sign for the Macon County airport and arrows and signs pointing left onto Airport Road. Be alert on the road, there are a few tight corners to be negotiated. Travel past the airport, running parallel to the runway. After that point you will come to a junction of Olive Hill Road where you will continue nearly straight. At this point you will stay on Olive Hill Road and up through the pass. At the pass you are about 2280 feet above sea level. Once in a while maybe a wild turkey may show itself! Continue for about 2 more miles, watch for our signs, and you will come down a fairly steep slope to what may appear to be a deadend, but this is where Upper Burningtown, Middle Burningtown, and Olive Hill roads intersect. Continue to the left, follow the double yellow centerline. Just around the first bend is a bridge which crosses a branch stream coming from a very pretty waterfall which feeds into the Burningtown Creek. Cross the bridge and continue the next intersection is Ray Creek Road and the Mt. Sinai Assembly of God. Continue across the bridge you are almost there. Just a few easy curves to 6961 Upperburningtown Road, where the gate will be open 7 days a week weather permitting. Enjoy your stay and make sure to ask for help if you need it.