1
Oxygen (O)
Nearly half the crust by mass: oxygen is bound into silicates, oxides and carbonates, and makes up 46.1% of crustal weight.
atomic_number: 8abundance_ppm: 461000goldschmidt_class: Lithophilecommon_form: Silicates, oxides, carbonates
Top 10 Most Abundant Elements in Earth's Crust
The ten most common chemical elements in Earth's continental crust by mass, per the CRC Handbook: oxygen alone is 46.1%, silicon 28.2%.
Quick answer
Oxygen (O) is the most abundant element in Earth's continental crust, at 46.1% by mass. Silicon (Si) is second at 28.2% and Aluminium (Al) third at 8.23%. The ranking uses estimated mass fraction in the continental crust from the CRC Handbook of Chemistry and Physics, 97th edition, as tabulated by Wikipedia, as of October 2026.
Earth's crust is a thin, solid outer shell made mostly of oxygen and silicon, which together account for about three-quarters of its mass. This list ranks the ten most abundant elements in the continental crust by mass fraction, using the estimates published in the CRC Handbook of Chemistry and Physics and reproduced in Wikipedia's table of crustal abundances. Oxygen leads at 46.1%, followed by silicon at 28.2%. With aluminium, iron, calcium, sodium, magnesium and potassium, these eight elements make up about 99% of the crust by mass; every other element together accounts for roughly 1%.
Mass fraction (%)
Oxygen (O)
Silicon (Si)
Aluminium (Al)
Iron (Fe)
Calcium (Ca)
Sodium (Na)
Magnesium (Mg)
Potassium (K)
Titanium (Ti)
Hydrogen (H)
The ranking
2
Silicon (Si)
The backbone of silicate minerals such as quartz, feldspar and mica, silicon makes up 28.2% of the crust by mass, almost always bonded to oxygen.
atomic_number: 14abundance_ppm: 282000goldschmidt_class: Lithophilecommon_form: SiO₂, silicates
3
Aluminium (Al)
The most abundant metal in the crust at 8.23%, aluminium is found in feldspars, micas and clays; it was not isolated as a metal until 1825.
atomic_number: 13abundance_ppm: 82300goldschmidt_class: Lithophilecommon_form: Feldspars, micas, clays, bauxite
4
Iron (Fe)
The most abundant transition metal in the crust, iron makes up 5.63% by mass, concentrated in mafic minerals and oxides such as hematite and magnetite.
atomic_number: 26abundance_ppm: 56300goldschmidt_class: Siderophilecommon_form: Silicates, hematite, magnetite
5
Calcium (Ca)
Calcium accounts for 4.15% of the crust, in limestone and marble (calcium carbonate), gypsum and plagioclase feldspar.
atomic_number: 20abundance_ppm: 41500goldschmidt_class: Lithophilecommon_form: CaCO₃, gypsum, plagioclase
6
Sodium (Na)
Highly reactive in pure form, sodium occurs in feldspar (albite) and halite (rock salt) and makes up 2.36% of the crust by mass.
atomic_number: 11abundance_ppm: 23600goldschmidt_class: Lithophilecommon_form: Albite, halite (NaCl)
7
Magnesium (Mg)
Magnesium makes up 2.33% of the crust, just behind sodium, and is concentrated in mafic and ultramafic rocks in minerals such as olivine, pyroxene and dolomite.
atomic_number: 12abundance_ppm: 23300goldschmidt_class: Lithophilecommon_form: Olivine, pyroxene, dolomite
8
Potassium (K)
Potassium comprises 2.09% of the crust, mainly in orthoclase feldspar and micas. Its radioactive isotope potassium-40 is one of the main sources of the heat generated inside the Earth.
atomic_number: 19abundance_ppm: 20900goldschmidt_class: Lithophilecommon_form: Orthoclase, muscovite
9
Titanium (Ti)
Titanium accounts for 0.565% of the crust, mostly in ilmenite and rutile; it is far less abundant than the eight major elements above it but still the ninth most common.
atomic_number: 22abundance_ppm: 5650goldschmidt_class: Lithophilecommon_form: Ilmenite (FeTiO₃), rutile (TiO₂)
10
Hydrogen (H)
Though the most abundant element in the universe, hydrogen makes up only about 0.14% of the crust by mass, bound in water, hydroxyl groups in minerals, and organic matter.
atomic_number: 1abundance_ppm: 1400goldschmidt_class: Atmophilecommon_form: H₂O, OH⁻ in clays and micas
Full comparison
| # | Name | atomic_number | abundance_ppm | goldschmidt_class | common_form |
|---|---|---|---|---|---|
| 1 | Oxygen (O) | 8 | 461000 | Lithophile | Silicates, oxides, carbonates |
| 2 | Silicon (Si) | 14 | 282000 | Lithophile | SiO₂, silicates |
| 3 | Aluminium (Al) | 13 | 82300 | Lithophile | Feldspars, micas, clays, bauxite |
| 4 | Iron (Fe) | 26 | 56300 | Siderophile | Silicates, hematite, magnetite |
| 5 | Calcium (Ca) | 20 | 41500 | Lithophile | CaCO₃, gypsum, plagioclase |
| 6 | Sodium (Na) | 11 | 23600 | Lithophile | Albite, halite (NaCl) |
| 7 | Magnesium (Mg) | 12 | 23300 | Lithophile | Olivine, pyroxene, dolomite |
| 8 | Potassium (K) | 19 | 20900 | Lithophile | Orthoclase, muscovite |
| 9 | Titanium (Ti) | 22 | 5650 | Lithophile | Ilmenite (FeTiO₃), rutile (TiO₂) |
| 10 | Hydrogen (H) | 1 | 1400 | Atmophile | H₂O, OH⁻ in clays and micas |
How we ranked this
Elements are ranked by estimated abundance in Earth's continental crust, in parts per million by mass, as given in the CRC Handbook of Chemistry and Physics, 97th edition (2016-2017), section 14, 'Abundance of Elements in the Earth's Crust and in the Sea', as tabulated in Wikipedia's Abundance of elements in Earth's crust. The metric is that value converted to percent (10,000 ppm = 1%). All ten values come from this one table; other compilations, such as Rudnick and Gao's estimate of continental-crust composition, give somewhat different figures and are not mixed in. Values are averages for the continental crust; oceanic crust and individual localities differ. Rank 1 is the most abundant; there are no ties.
FAQ
What is the most abundant element in Earth's crust?
Oxygen, at about 46.1% by mass in the CRC Handbook estimate. It is bound with silicon and metals in the silicate and oxide minerals that make up most rocks.
What is the most abundant metal in Earth's crust?
Aluminium, at about 8.23% by mass. It is the third most abundant element overall, after oxygen and silicon, and ahead of iron at 5.63%.
How do crustal abundances differ from the whole Earth or the universe?
Sharply. Iron, which sank to form the core, is far more abundant in the Earth as a whole than in the crust, while the crust is enriched in lighter elements such as oxygen, silicon and aluminium. The universe is dominated by hydrogen and helium, which are rare in the crust.
What are Clarke numbers?
Clarke numbers are estimates of the average abundance of elements in Earth's crust, named after the American geochemist Frank Wigglesworth Clarke (1847-1931), who compiled early estimates. Modern compilations such as the CRC Handbook table used here continue that work.
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