Palmoxylon (Petrified palmwood), is an extinct genus of palm named from petrified wood found around the world. Specimens from the Oligocene epoch (34 - 23 mya) can be collected from many scattered sites in western Louisiana. Petrified palmwood includes a group of fossil woods that contain prominent rod-like structures within the regular grain of the silicified wood. Depending upon the angle at which they are cut by fracture, these rod-like structures show up as spots, tapering rods, or continuous lines. Petrified palmwood is a favorite of rockhounds because it is replaced by quartz and exhibits well-defined rod-like structures and variety of colors. As a result, it exhibits a wide range of colors and patterns.Because it is composed of silica, it is hard enough to polish and withstand the wear and tear of normal use.

Petrified palmwood is most common in the Toledo Bend area. It was left by trees that grew when the Gulf  of Mexico's shoreline was much farther north from its present day position. In Louisiana, petrified palmwood is found in the parishes of Rapides, Natchitoches, Grant, and Sabine.