Ruby John, 26, is a jewel of a girl. Her name fits her. She’s also a gifted and versatile fiddler. One balmy Friday evening in mid-June she’s entertaining families at the Little Traverse Inn, fiddling in the Ruby Sky Band with some of her friends: Dane Hyde, who sings and plays guitar; Katie O’Conner, a singer and Irish dancer; and John Driscoll, a flautist and singer. The next week she’ll play for a staff dance at the Interlochen Arts Academy’s opening of summer camp. And after that, Saturday July 15, from 7 p.m.-1 a.m., Tucker’s in Northport. She’s known for playing a Métis-style of fiddle as well as Celtic, and standard country-and-mountain-style.