![]() ![]() Oxygen and silicon are perhaps the best examples. Some elements are common in many different minerals. Nonetheless, in most settings, we can expect common minerals to be made of the elements shown in the histograms above. And, the composition of the shallow crust is somewhat different from the deep crust. For example, the oceanic crust is not the same composition as the continental crust. The compositions of Earth’s outer layers vary somewhat laterally and vertically. And other generally rare elements are sometimes concentrated by geological process to make exotic minerals. Hydrogen (0.15 wt%) and carbon (0.18 wt%) are overall minor elements in the crust but are key components in some minerals. However, the mantle contains much more magnesium and iron, and less silicon, than the crust. Other quite abundant elements in both the crust and mantle include aluminum, iron, calcium, sodium, potassium, and magnesium. Together these two elements make up about three quarters of the crust, and two thirds of the mantle. In both places, oxygen and silicon are the dominant elements (Figures 2.2 and 2.3). Most of the minerals and other geological materials we see derive from the crust, but some come from the uppermost part of the mantle. And, the core is completely different from the crust and mantle – it is mostly iron with perhaps 20% nickel and lesser amounts of other elements. Although Earth’s crust and mantle contain the same major elements, the proportions are not the same (see histograms below). Earth, however, is dominated by other elements, and 8 to 10 elements account for most of Earth’s mass. For example, the matter of the Milky Way, our galaxy, is mostly hydrogen and helium – the same elements that make up >99% of our sun. Although 1000s of minerals are known, only a small number are common.Īll matter is made of atoms of individual elements.Weight % values can be normalized to give chemical formulas.We describe mineral compositions by giving weight %s of the elements or oxides present.The kind of bonding affects mineral properties.Ionic, covalent, or metallic bonding are most common in minerals.Elements with similar properties may substitute for each other in minerals and many minerals have variable compositions.The Periodic Chart of the Elements orders elements by their atomic number and groups elements with similar properties.8 to 10 elements account for most of Earth’s mass but the elements are distributed unevenly.All matter, including mineral matter, is made of elements.2.1 Carrollite has the formula Cu(Co,Ni) 2S 4 ![]()
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