Mineral Groups Nearly 4000 minerals have been discovered

Mineral Groups 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. Minerals that form the rocks within Earth’s crust belong to seven (7) main mineral groups, which include: 1) Silicates 2) Carbonates 3) Sulfates 4) Oxides 5) Halides Reference: 6) Sulfides Tarbuck and Lutgens 7) Native Elements Pages 44 - 55

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 Mineral groups that end with “ate” and have an oxygen group in its chemical formula are one of the following; Silicates = Si + Oxygen Olivine (Mg, Fe)2 Si. O 4 Sulfates = S + Oxygen Barite Ba. SO 4 Carbonates = C + Oxygen Calcite Ca. CO 3

Hints to Classify Mineral Groups 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 Hematite Fe 2 O 3 Sulfides = Metal + S Pyrite Halides = Metal + Cl, Br, F Fluorite Fe. S 2 Ca. F 2

Mineral Groups 1) Silicates v A mineral group that has silicon and oxygen as part. of their atomic structure. v Comprise more than 96% of the crust (most common mineral group). Rock forming silicates are divided into two groups: Sialic Silicates (Aluminosilicates) Examples include: Ø Rich in silicon and aluminum. Quartz Ø Comprise about 85% of the silicates in the crust. Mica (Muscovite) Ø Mineral are light in color. Feldspar

Mineral Groups 1) Silicates (Continued) Simatic Silicates Ø Rich in silicon and magnesium. Ø Comprise less than 15% of the silicates in the crust. Ø Minerals are dark in colour. Examples include: Olivine Pyroxene Amphibole

Mineral Groups 2) Carbonates v compounds consisting of an atomic structure of one carbon and three oxygen (CO 3). v most common carbonate mineral is calcite (Ca CO 3), which makes up the chemcial sedimentary rock called limestone as well as the metamorphic rock called marble. 3) Sulfates v compounds consisting of an atomic structure of one sulfur and four oxygen (SO 4). v the rock gypsum is an example of a sulfate and it also takes on the mineral name. (Ca. SO 4 • 2 H 2 O) v. The mineral barite (Ba. SO 4) is mined and used in drilling mud.

Mineral Groups 4) Oxides v compounds consisting of an atomic structure of oxygen combined with one or more metals. v most common oxides are those of iron (Fe 2 O 3) and aluminum (Al 2 O 3); referred to as the Ore Minerals. As an example, the mineral hematite is Fe 2 O 3 5) Halides v compounds consisting of an atomic structure of chlorine or fluorine with sodium, potassium, or calcium. v Halite (Na. Cl) is the most common halide. It is often referred to as table salt.

Mineral Groups 6) Sulfides v compounds consisting of an atomic structure of one or more metals combined with sulfur. v examples of minerals include: pyrite (Fe. S 2), galena (Pb. S), and sphalerite (Zn. S). 7) Native Minerals v elements that occur uncombined in nature. v commonly called native elements. v 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) (B) (C) (D) barite (Ba. SO 4) calcite (Ca. CO 3) fluorite (Ca. F 2) hematite (Fe 2 O 3)