Earth 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).
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 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 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 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
Mineral 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