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How does Mercury’s surface composition differ from the Moon’s surface?

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Messenger: Mercury — Mercury Mercury as seen by the Messenger probe, January 14, 2008. This image shows half of the hemisphere missed by Mariner 10 in 1974–75 and was snapped by Messenger's Wide Angle Camera when it was about 27,000 km (17,000 miles) from the planet.

While Mercury and the Moon appear superficially similar due to their heavily cratered terrains, their surface compositions differ significantly.12

Data from the Messenger spacecraft revealed that Mercury’s crust is not rich in feldspar, unlike the lunar highlands. Furthermore, Mercury’s surface is notably rich in sulfur—approximately 20 times more abundant than on the surfaces of the Moon, Earth, or Mars.3

Chemically, Mercury exhibits a high ratio of magnesium to silicon, alongside low ratios of aluminum and calcium to silicon. Additionally, the planet shows low surface abundances of titanium and iron. In contrast, lunar surfaces are characterized by basalts (often rich in iron and titanium) in the maria and anorthosites (rich in aluminum, calcium, and silicon) in the highlands. Finally, Mercury lacks the extensive dark-coloured lava flows known as maria that are prominent on the Moon.341