By Philippe Mathelet
The Earth and Minerals
Composition of the earth: fewer than 10 chemical elements account for more than 99% by weight of the Earth's composition
Fewer than 10 chemical elements account for more than 99% by weight of the Earth's composition
The composition and abundance of minerals reflect this distribution of chemical elements in the different layers of the Earth.
The composition of the Earth as a whole cannot be measured directly. It can be estimated by comparison with meteorite analyses and the composition of the sun's photosphere.
The different elements of the periodic table do not have the same abundance on Earth. Fewer than 10 elements account for more than 99% by weight of the whole Earth.
The most important rock-forming elements are iron and oxygen, followed by silicon and magnesium.
The continental and oceanic crusts form the best-known part of our planet, but represent only a small volume compared to the Earth as a whole (crust thickness between approximately 0-30 km for an Earth radius of about 6370 km). The composition of the crusts fundamentally differs from that of the whole Earth.
The most striking difference is the high abundance of oxygen, silicon and to a lesser extent aluminium in the Earth's crusts.
Most chemical elements on Earth combine to form solid crystalline substances, minerals. One exception concerns the outer core which does not behave as a solid body. Because of this, the most abundant minerals mainly combine the dominant chemical elements presented in the abundance table.
Many elements do not directly enter as major elements in the composition of minerals but can substitute for other major elements.
These articles are for information only and are neither medical advice, nor a diagnosis, nor a prescription.
The articles in this section reflect the experience and reading of their author, who does not practise any medical profession. They are published for information and never replace a consultation with a doctor or pharmacist. Food supplements are not medicines. If you are under treatment, pregnant, breastfeeding or ill, ask a health professional before any use.