If you visit the UP you might like The Agate Lady...

http://www.agatelady.com/gift-shop.html

There is also a seller on Ebay called Rock Whisperer...who paints realistic turtles and animals on round rocks... they are really awesome. She is very popular now.
http://www.ebay.com/usr/rock_whisper...88.m1543.l2754
She only has one item now, a raccoon.
She lives in Bay City and has access to a huge commercial rock pile along the Saginaw river where she can choose the shape and size of her starting rocks for paintings. She sometimes finds puddingstones (jaspar conglomerates) in that pile too and sells them raw on Ebay.
Her turtles look totally REAL.

I've been to Whitefish point in the UP and collected stones many years ago. My MIL had a gift shop and wanted some painted stones and since I am an artist I did some for her then. They nowhere were as good as Rock Whisperer on Ebay!

photo #1 is a small sphere of quartz and citrine quartz
Photo #2 is a larger one with quartz and amethyst crystal

I bought most of my stones on Ebay. I like rock too and we have plenty around our summer place to do various things with!
(but not as nice as Lake Superior rock )

Here is one crystal sphere I did -- about 3 yrs ago... I did several and gave them as gifts...