I’m not sure where the game orginates but it was originally played with small smooth stones about pebbles sized and so was called Jack stones. i’ve seen children in Africa playing something like it.
You can buy really nice heavy brass jacks from Hearthsong (www.hearthsong.com)
The Mother Goose rhyme of Jack be nimble has nothing to do with the game; it’s a riddle and Jack is the flame.
Hearthsong also has rules of the game including the fancies.
Any one remember how the various fancies are played? I want to teach some to my daughters