Praxiteles is a crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 on Mercury

Mercury (planet)

Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...

.

MESSENGER

MESSENGER

The MErcury Surface, Space ENvironment, GEochemistry and Ranging space probe is a robotic NASA spacecraft in orbit around the planet Mercury. The spacecraft was launched aboard a Delta II rocket in August 2004 to study the chemical composition, geology, and magnetic field of Mercury...

's high-resolution images obtained during the mission's second Mercury flyby have revealed a number of irregularly shaped depressions on the floor of Praxiteles crater, making it a pit-floor crater. The colors near these depressions in WAC images are similar to those near volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

es discovered during the mission's first Mercury flyby along the inner edge of the Caloris basin

Caloris Basin

The Caloris Basin, also called Caloris Planitia, is a large impact crater on Mercury about in diameter, one of the largest impact basins in the solar system. Caloris is Latin for heat and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion...

. The similar colors and the association with the irregular depressions (possible volcanic vents) are suggestive of past volcanic activity on the floor of Praxiteles.

Praxiteles crater was first observed by Mariner 10.