Mineral Groups

Reference: Tarbuck and Lutgens Pages 44 - 55

Minerals that form the rocks within Earth’s crust belong to seven (7) main mineral groups, which include:1) Silicates

2) Carbonates3) Sulfates4) Oxides5) Halides6) Sulfides

7) Native Elements

Nearly 4000 minerals have been discovered and named; however, no more than a few dozen are abundant. These few dozen makes up most of the rocks that comprise Earth’s crust. This is why we call them the rock-forming minerals.

Do You Remember?• Do you remember the eight elements that

make up more than 98 % of Earth’s crust (i.e. continental crust)? List them.

• Which two elements are most abundant in Earth’s crust? Oxygen and Silicon.

• Both comprise nearly three-fourths of Earth’s continental crust. Both elements combine to form the framework of the most common mineral group (i.e. the silicates).

• The framework is called the silicon-oxygen tetrahedron.

Hints To Classify Mineral Groups

Olivine (Mg,Fe)2SiO4

Barite BaSO4

Calcite CaCO3

Mineral groups that end with “ate” and have an oxygen group in its chemical formula are one of the following;

Silicates = Si + Oxygen

Sulfates = S + Oxygen

Carbonates = C + Oxygen

Hints to Classify Mineral Groups

Hematite Fe2O3

Pyrite FeS2

Fluorite CaF2

Mineral groups that end with “ide” and have a metal (e.g., Na, K) in its chemical formula are one of the following;

Oxides = Metal + O

Sulfides = Metal + S

Halides = Metal + Cl, Br, F

Mineral Groups

Silicates1) A mineral group that has silicon and oxygen as part . of their atomic structure. Comprise more than 96% of the crust (most common mineral group).

Rock forming silicates are divided into two groups:

Sialic Silicates (Aluminosilicates) Rich in silicon and aluminum.

Comprise about 85% of the silicates in the crust.

Mineral are light in color.

Examples include:

Quartz

Mica (Muscovite)

Feldspar

Mineral Groups

Silicates (Continued)1)

Simatic Silicates Rich in silicon and magnesium.

Comprise less than 15% of the silicates in the crust.

Minerals are dark in colour.

Examples include:

Olivine

Pyroxene

Amphibole

Mineral GroupsCarbonates2) compounds consisting of an atomic structure of one carbon and three oxygen (CO3).

most common carbonate mineral is calcite (Ca CO3), which makes up the chemcial sedimentary rock called limestone as well as the metamorphic rock called marble.Sulfates3) compounds consisting of an atomic structure of one sulfur and four oxygen (SO4). the rock gypsum is an example of a sulfate and it also takes on the mineral name. (CaSO4 • 2H2O)

The mineral barite (BaSO4) is mined and used in drilling mud.

Mineral Groups

Oxides4) compounds consisting of an atomic structure of oxygen combined with one or more metals.

most common oxides are those of iron (Fe2O3) and aluminum (Al2O3); referred to as the Ore Minerals. As an example, the mineral hematite is Fe2O3

Halides5) compounds consisting of an atomic structure of chlorine or fluorine with sodium, potassium, or calcium.

Halite (NaCl) is the most common halide. It is often referred to as table salt.

Mineral Groups

Sulfides6) compounds consisting of an atomic structure of one or more metals combined with sulfur.

examples of minerals include: pyrite (FeS2), galena (PbS), and sphalerite (ZnS).

Native Minerals7) elements that occur uncombined in nature.

commonly called native elements.

examples include: gold (Au), silver (Ag), copper (Cu), and sulfur (S).

NOTE

• Note that an ore mineral is any mineral that has enough of a particular element in it to be mined at a profit.

Sample Problem

Which is an example of a halide?

(A) barite (BaSO4) (B) calcite (CaCO3) (C) fluorite (CaF2) (D) hematite (Fe2O3)