There are books about the value of old marbles...
The valuable old marbles are those that were hand made from a rod of glass, crockery or stone.
The ones made from a rod are variously classified as open core, swirl, onion skin and various kinds of closed core marbles.
Then there are the solid color opaque glass marbles. A hand made glass marble is ID'd by the pontil mark on both ends....some are finished very well but you cans till see...
Then there are the "bennies"...Bennington glazed crockery marbles..in shades of blue and browns and mixed.
Then come the aggies....which are made from stone...agate...with a good glass you can sometimes see the marks where the stone was worked....and they come in all sized and in colors of agate...I have a shooter in a lovely milky calcedney.
Then there are the sulfides....which are clear glass with a small white figure imbedded...often a rooster or another animal...usually a shooter....sometimes even bigger....and often chipped because kids used them to shoot other marbles out of the ring.
And there are bulls eyes...white crockery with a painted on bulls eye in red or blue...and comic book marbles which have comic book figures printed on them, and mica flake...clear glass, hand made with flecks of mica in them...
And then there are the early machine made...like those made by Akro Agate...If you find a set of them in a box you have found a treasure. Machine mades are variously bumble bees, swirls etc etc...
Sorry you asked??? LOL!!
Linda c

The best marbles were made of agate. As agate became scarce and rockhounds realized its value, it became too expensive and rare for production marbles. Other materials took over the market. Many were manufactured to emulate the appearnace of agate.

Back in the "good ole days", a meanie (who was loosing) with an "aggie" shooter could break his opponent's glass marbles by going for the hardest hit he could muster rather than using finese designed for winning shots.