We visited this mine on July 2 driving about 1 1/2 hours to get there from the Sapphire Valley/Cashiers area. It was well worth the drive - but don't follow your GPS - follow the directions on the mine's web site. Our GPS led us to some gated community off of Hwy 23. Once we got back into the town of Franklin, we found our way to the mine which is just a short drive out of town. We arrived and got our briefing from the owner who helped us all day along with her son. As other reviews say, this mine does not "salt" their dirt - so what you find will be authentic native gems. You do have to sort through your stones carefully to find something of value which can be easy to miss. However, after you sort through your gravel, you put it all in an empty bucket and then the owner or her son go through it again looking for anything you might have missed. We did miss a couple sapphires and other things which they salvaged for us. They were supposed to close at 4 PM, but we didn't end up leaving until after 5 since we got a late start.
The owner is a very nice lady who talks much like a teacher telling us all about each type of stone and how some of the ones we had weren't really gemstones but how they could still polish up nicely if we wanted to use them for something. She had been friends with the previous owners of the mine for years and learned from them how to identify the stones. She took a lot of time with my daughters going over several types of stones and showing them what to look for.
At the end of the day, the owner said she had been mining a little earlier in the day and brought out her bottle of gems to show us. After she poured them all out to show my daughters, she told them they could have them all!! This was a real treat. We spent a lot of time talking to the owner about the history of the mine and her love for mining as well as the history of the area.
I don't have any basis for comparison of this mine versus others, but I can tell you our experience was 100% positive and we'd recommend this mine any time. You do need to be patient as it takes a whole to sort through your dirt, but you may just find something nice. The cost was fairly small - $15 each which included two buckets of dirt for each person. We thought we would end up buying more dirt, but it took us about an hour per bucket to go through our dirt so we didn't end up buying any more.