Topic F1: ELEMENTS, MINERALS AND ROCKS
Key Idea 1: The Earth is composed of rocks which have distinctive mineralogies and textures
Goldschmidt system
Siderophile - having so little affinity for oxygen and sulphur that in a molten mass the greatest concentration (as of
an element) would be found in the metallic phase (as in the iron of a blast furnace), siderophile itself means iron-
loving as iron is very dense thus the iron core
Chalcophile - having such an affinity for sulphur that in a molten mass the greatest concentration (as of an element)
is found in the sulphide phase.
Lithophile - Lithophile is a term used to refer to elements that are preferentially partitioned into silicate minerals as
opposed to sulphides or metals.
Atmophile - found in, attracted to, or tending to occur in the atmosphere —used especially for chemical elements or
compounds. It binds mostly to oxygen thus has a low density and is found in the atmosphere.
Silicate Minerals
The most common cation in the crust is Silicon (27%) and the most common anion in the crust is Oxygen (46%)
Therefore, most of the minerals that make up the rocks of Earth’s crust are silicate minerals. These include minerals
such as quartz, feldspar, mica, amphibole (hornblende), pyroxene (augite), olivine, and a great variety of clay
minerals.
Silicon and oxygen bond together to create a silica tetrahedron,
which is a four-sided pyramid shape with O at each corner and Si
in the middle. This structure is the building block of the many
important silicate minerals.
The bonds in a silica tetrahedron have some of the properties of
covalent bonds and some of the properties of ionic bonds. As a
result of the ionic character, silicon becomes a cation (with a
charge of +4) and oxygen becomes an anion (with a charge of –2). The net charge of a silica tetrahedron (SiO4) is –4.
In silicate minerals, these tetrahedra are arranged and linked together in a variety of ways,
from single units to complex frameworks.
Each tetrahedron may be isolated from one another or they may be bonded together
covalently by sharing oxygen atoms between adjacent tetrahedra. In this way they may form
single chains , double chains , sheets and three-dimensional networks of interlocking
tetrahedra.
Key Idea 1: The Earth is composed of rocks which have distinctive mineralogies and textures
Goldschmidt system
Siderophile - having so little affinity for oxygen and sulphur that in a molten mass the greatest concentration (as of
an element) would be found in the metallic phase (as in the iron of a blast furnace), siderophile itself means iron-
loving as iron is very dense thus the iron core
Chalcophile - having such an affinity for sulphur that in a molten mass the greatest concentration (as of an element)
is found in the sulphide phase.
Lithophile - Lithophile is a term used to refer to elements that are preferentially partitioned into silicate minerals as
opposed to sulphides or metals.
Atmophile - found in, attracted to, or tending to occur in the atmosphere —used especially for chemical elements or
compounds. It binds mostly to oxygen thus has a low density and is found in the atmosphere.
Silicate Minerals
The most common cation in the crust is Silicon (27%) and the most common anion in the crust is Oxygen (46%)
Therefore, most of the minerals that make up the rocks of Earth’s crust are silicate minerals. These include minerals
such as quartz, feldspar, mica, amphibole (hornblende), pyroxene (augite), olivine, and a great variety of clay
minerals.
Silicon and oxygen bond together to create a silica tetrahedron,
which is a four-sided pyramid shape with O at each corner and Si
in the middle. This structure is the building block of the many
important silicate minerals.
The bonds in a silica tetrahedron have some of the properties of
covalent bonds and some of the properties of ionic bonds. As a
result of the ionic character, silicon becomes a cation (with a
charge of +4) and oxygen becomes an anion (with a charge of –2). The net charge of a silica tetrahedron (SiO4) is –4.
In silicate minerals, these tetrahedra are arranged and linked together in a variety of ways,
from single units to complex frameworks.
Each tetrahedron may be isolated from one another or they may be bonded together
covalently by sharing oxygen atoms between adjacent tetrahedra. In this way they may form
single chains , double chains , sheets and three-dimensional networks of interlocking
tetrahedra.
