Piffka: The Agate, or Aggie, (no, that's not how I chose my screen name, lol), was rarer and larger and was prized as a shooter. Sometimes the prize for winning was the other player's shooter. The smaller marbles were usually Cats Eye. You were probably a little lady and not a "tomboy" like I was. My Mom frowned upon the unladylike game, but was sweet enough to make me a drawstring felt bag with my initials embroidered on it to carry the marbles. The boys were so jealous, Mom made them marble bags, too. I started shooting marbles at age 5 and have a photo of me in overalls and cap shooting my Agate.
The marble ring had to be dry dirt, but to tell you the truth, I don't remember ever washing those marbles. The game dates back to ancient Egypt and marble championships are held in many parts of the world today. (I just read that it was one of Abraham Lincoln's favorite games.) I was going to post a link of the game's history here, but it didn't work.
I'll have to learn how to do that. The marbles came in all colors and designs and the real incentive of the game (at least for me) was winning the prettiest marbles.