Marble is a white mineral which, because of its great beauty and sheen, is often used for buildings and sculpture.
It is actually limestone that was turned into crystals by millions of years of pressure under the earth. Sometimes, impurities in the limestone produce colored marble, such as pink, red, or green marble, or marble streaked with colors.
But the small balls that are used to play a game of marbles are not made of marble, as this substance is too expensive to be used in ordinary toys. Most marbles are made from glass, clay, plastic, or stone.
The largest single piece of marble ever mined weighed over 200,000 pounds.