Are moon rocks heavy?

Solid moon rocks are often denser than many common Earth rocks of the same type, especially iron-rich mare basalts, but porous highland rocks and impact breccias can be lighter. Laboratory measurements on Apollo samples and lunar meteorites find mare basalt grain densities around 3.3–3.5 g/cm³ (bulk densities often near 3.0–3.3 g/cm³ after porosity), while feldspathic highland rocks and breccias commonly have lower bulk densities, roughly mid-2 g/cm³ when porosity is high.

So a hand sample can feel “heavy” for its size if it is dense basalt, or surprisingly light if it is a porous breccia—density depends on rock type and pore space, not a single Moon-wide value.

Source: Macke et al., LPSC 2010 abstract 1252 (Lunar and Planetary Institute) — density and porosity of lunar rocks.

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