| 2026-06-14 | Volcanic gems found on every continent |
| 2025-06-08 | Striped stones |
| 2024-04-17 | Banded gemstones |
| 2023-11-27 | Colorful banded rocks |
| 2019-02-07 | Banded stones |
| 2016-03-30 | Shooting marbles |
| 2015-07-30 | Swirly-colored marbles |
| 2014-04-09 | Banded gemstones |
| 2013-04-08 | Playing marbles |
| 2012-06-04 | Some marbles |
| 2012-01-17 | Banded marbles |
| 2012-01-01 | Swirly marbles |
| 2011-10-30 | Ancient May birthstones |
| 2011-02-27 | Striped stones |
| 2010-11-15 | Playing marbles |
| 2010-07-10 | Balls with bands |
| 2010-02-19 | Cat's-eye relatives |
| 2009-07-15 | Playing marbles |
| 2008-10-01 | Semiprecious stones |
| 2007-09-03 | They're seen at marble tournaments |
| 2006-01-23 | Playing marbles |
| 2004-12-12 | Small types |
| 2003-06-03 | Playing marbles |
| 2002-05-13 | Some marbles |
| 2001-12-30 | Small types |
| 2001-06-26 | Playing marbles |
| 2001-02-24 | They're used in classified ads |
| 1999-09-13 | Glass marbles |
| 1999-06-06 | 5.5-point type sizes |
| 1997-05-14 | Playing marbles |
| 1997-04-14 | Certain marbles |
| 1997-02-09 | Marbles |
| 1995-12-25 | Playing marbles |
| 1995-03-19 | Migs' relatives |
| 1994-11-17 | Some chalcedonies |