The big four is probably four machine made marble companies, Akro-Peltier-CAC-Vitro ?? The original group if 1/2 inch or less in size ? I think he was saying that probably the only marble in the group that would be much interest to collectors or with much value would be the far left maybe a Peltier. Any marble can be collectable to someone someplace for many different reasons. But collectable has a wide range of value from zero to some and more for others. There can be a big difference in wanting to know what a marble is or who made it or when it was made. The other side is what is it worth. The value side has lots of variables. Depending on if it is purchased for a aquarium, a flower pot, crafts, for kids play, to learn from or to collect seriously. If people just want a value, they should let that be known and for what purpose. Many times it is asked, what is it called. For nothing but a value or a way to sell it. That is fine but it helps if people know what the true question is ? The original post may be a collector or a seller or both. All are fine, but things are easier if we know what is needed for what ? Most all marbles at 1/2 inch size and smaller are known by marble collectors as pee wee's. To get a accurate marble measurement, a caliper should be used. Not a carpenters square. At 1/64 of one inch over 1/2 inch and it is not a pee wee. There are different companies marbles in the group. Hope this was help and not misleading. Which no one here will try to do.