Mineral deposits can create markings that look like forests or mountains, and experts say each stone is distinctive. By Jill Newman When Tarun Adlakha displays a dendritic agate, with its finely ...

If you’ve held onto old marbles from childhood or stumbled across a dusty jar in the attic, you might be wondering if they’re worth anything. Not all old marbles have high value, but certain handmade, ...