Introduction to MineralsIntroduction to Minerals

Earth MaterialsEarth Materials

• Mineral:

– Naturally occurring

– Solid substance

– Orderly crystalline structure

– Definite chemical composition

– Generally inorganic

Earth MaterialsEarth Materials

• Rock: any solid mass of mineral, or mineral-like matter that occurs naturally as part of the planet.

– Some rocks composed entirely of one mineral.

– Most are aggregates of several kinds of minerals.

– Some rocks are composed of nonmineral matter (glass and organic materials).

ElementsElements

• Element: a substance that cannot be broken down into simpler substances by chemical or physical means.

– Composed entirely of one type of atom.

Some minerals are a single elementSome minerals are a single element

• Compound: a substance consisting of atoms of different elements.

• Chemical Bond: the sharing or transfer of electrons between atoms in order to attain stable electron configurations.

Many minerals are compoundsMany minerals are compounds

• Crystal Form or Habit: external expression of a mineral’s internal orderly arrangement of atoms.

– Individual crystals with well-formed faces occur when there are no space restrictions during growth.

Quartz Crystals commonly occur as hexagonal prisms

• Only 8 elements make up the bulk of rock-forming minerals and represent over 98% of the continental crust.

Mineral GroupsMineral Groups

• Silicon and Oxygen are the most abundant elements in Earth’s crust.

• Si and O combine to form the framework of the most common mineral group: the Silicates.

– Silicates account for more than 90% of Earth’s crust.

Silicate MineralsSilicate Minerals

• Silicon Tetrahedron – one Si atom bonded with four O atoms.

– Fundamental building block of silicates.

Different groups of silicates consist of silicon tetrahedra joined together in different ways - common elements that join silicate structures are Fe, Mg, K, Na, Ca

2 most abundant silicate minerals:2 most abundant silicate minerals:

• Feldspars make up more than 50% of Earth’s crust.

• Quartz is the second most abundant mineral in continental crust.

Mineral GroupsMineral Groups

• Nonsilicates: much less abundant in Earth’s crust.

– Many are of economic importance.

– Examples: metallic ore minerals and precious gemstones.

• Major constituents in sedimentary rocks:

– Examples: calcite, gypsum, and halite