What Is the Moon Made Of?
The Moon is made mostly of silicate rock, oxygen, magnesium, silicon, iron, calcium, and aluminum, arranged into a crust, mantle, and small core.
Its chemistry looks familiar in some ways, but key differences from Earth help explain why the Moon formed and evolved the way it did.
Scientists know this from Apollo samples, lunar meteorites, orbiters such as NASA’s Lunar Reconnaissance Orbiter, and spectrometers that measure the Moon’s surface from space.
The most interesting part is not just what is present, but what is missing: the Moon is depleted in water and volatile elements compared with Earth.
The Moon’s Main Ingredients
The Moon is dominated by rocky minerals rather than metal or ice.
Its surface and interior are rich in silicate minerals, which are built from oxygen combined with elements such as silicon, magnesium, and iron.
- Oxygen: the most abundant element in lunar rocks, mostly bound in minerals rather than free as a gas.
- Silicon: a major building block of lunar silicates.
- Magnesium: common in the lunar mantle and in basaltic rocks.
- Iron: present in both silicate minerals and the small metallic core.
- Calcium and aluminum: especially abundant in the lunar crust.
In broad terms, the Moon is a rocky body with a composition closer to Earth’s outer layers than to the gas giants or icy moons of the outer solar system.
What Minerals Are on the Moon?
Lunar rocks contain several familiar minerals found on Earth, but in different proportions.
The most important are the following.
Plagioclase feldspar
Plagioclase feldspar is the dominant mineral in the Moon’s crust, especially in the bright highlands.
This mineral is rich in calcium and aluminum and is one reason the highlands reflect so much sunlight.
Pyroxene and olivine
These magnesium- and iron-rich silicate minerals are common in the lunar mantle and in volcanic rocks called basalts.
They are especially important in the darker maria, which are ancient lava plains.
Ilmenite
Ilmenite is an iron-titanium oxide found in some mare basalts.
It matters to scientists because it can indicate titanium-rich regions and is relevant to future resource use.
Glass and impact breccias
The Moon’s surface has been blasted by billions of years of impacts, producing glassy particles and breccias, which are rocks made of broken fragments cemented together.
These materials tell the story of lunar bombardment over time.
How Is the Moon Structured Inside?
The Moon is not a uniform ball of rock.
It has distinct layers that formed early in its history as heavier materials sank inward and lighter materials rose toward the surface.
The crust
The lunar crust is the outer shell, averaging roughly 30 to 50 kilometers thick, though it varies across the Moon.
The far side crust is generally thicker than the near side crust, a major clue in understanding lunar geology.
The crust is made mostly of anorthosite, a rock dominated by plagioclase feldspar.
This composition supports the idea that the Moon once had a global magma ocean.
The mantle
Below the crust lies the mantle, made of denser silicate rocks rich in magnesium and iron.
Much of what scientists infer about the mantle comes from volcanic samples, seismic data, and gravity measurements rather than direct drilling.
The core
The Moon has a small metallic core, composed mostly of iron with some nickel and sulfur.
Compared with Earth’s core, it is tiny, which is one reason the Moon has no strong global magnetic field today.
Why Do the Lunar Highlands and Maria Look So Different?
The Moon’s light-colored highlands and dark maria differ because they have different compositions and geologic histories.
The highlands are older and dominated by aluminum-rich crustal rocks, while the maria are younger basaltic plains formed by volcanic eruptions.
- Highlands: bright, ancient, heavily cratered, and rich in plagioclase feldspar.
- Maria: darker, smoother, younger, and formed by basaltic lava flows.
This contrast gives the Moon its famous face from Earth and reflects a long history of impacts and volcanism.
What Is the Moon Made Of Compared With Earth?
Earth and the Moon share many chemical similarities, but they are not identical.
Earth has far more iron in its core, more water at the surface, and a more active geology driven by plate tectonics, oceans, and an atmosphere.
The Moon is depleted in volatile elements, meaning it has much less material that easily evaporates or condenses at low temperatures.
This includes water, sulfur, zinc, and potassium in many lunar materials.
That depletion is one of the strongest clues that the Moon formed in a very high-energy event.
Does the Moon Have Water?
Yes, but not in large amounts compared with Earth.
Water has been detected in permanently shadowed craters near the poles, where temperatures are extremely low, and traces of hydroxyl and water-related molecules have also been found in surface minerals.
Most lunar water is not spread evenly across the Moon.
It appears as ice in cold traps, bound within minerals, or temporarily present in the thin surface layer known as the regolith.
This makes water a scientifically important and practical target for future lunar exploration.
What Is the Moon’s Surface Made Of?
The visible surface is a layer of regolith, a loose blanket of dust, soil, shattered rock, and tiny glass fragments produced by impacts and micrometeorite strikes.
Regolith thickness varies from place to place and can be only a few meters in some areas or much deeper in older terrain.
Regolith is not just dust.
It contains:
- mineral grains from the crust and mantle
- impact glass from melted rock
- tiny iron particles formed by space weathering
- lunar rock fragments and soil aggregates
Space weathering gradually darkens and changes the optical properties of regolith, which is why fresh crater rays can look brighter than older terrain.
How Do Scientists Know What the Moon Is Made Of?
Researchers combine several methods to identify lunar composition with high confidence.
Each method contributes different evidence.
- Apollo samples: rock and soil brought back by astronauts provided direct laboratory analysis.
- Lunar meteorites: natural samples ejected from the Moon and found on Earth broaden the range of known lunar materials.
- Spectroscopy: spacecraft measure reflected light to infer minerals and elements.
- Gravity mapping: changes in gravity reveal differences in density and subsurface structure.
- Seismology: Apollo seismometers helped estimate the Moon’s interior layers and core properties.
Together, these techniques show a body made mostly of differentiated rock, shaped by early melting, impact mixing, and volcanic resurfacing.
Why the Moon’s Composition Matters
Knowing what the Moon is made of helps scientists understand how the Earth-Moon system formed, how the lunar surface evolved, and where useful resources may exist for future missions.
It also helps refine models of planetary formation throughout the solar system.
The Moon preserves an early chapter of planetary history because it lacks atmosphere, active plate tectonics, and widespread erosion.
That makes its composition a relatively ancient record of solar system processes.
Key Takeaways About What the Moon Is Made Of
- The Moon is mostly silicate rock, not metal or ice.
- Its crust is rich in plagioclase feldspar and its mantle contains pyroxene and olivine.
- It has a small iron-rich core.
- Its surface is covered by regolith made from impacts and space weathering.
- It contains some water, but far less than Earth.
- Its chemistry reveals a violent origin and a long geologic history.