What is a mineral. Do Now: What do you know about minerals What is a mineral? Do Now: What do you know about minerals? HW: Minerals worksheet

Mineral Characteristics A mineral is a naturally occurring, inorganic solid, with a specific chemical composition and a definite crystalline structure. Copyright © McGraw-Hill Education What is a mineral?

Mineral Characteristics Naturally occurring and inorganic Minerals are naturally occurring, meaning that they are formed by natural processes. All minerals are inorganic: they are not made from living organisms. Definite crystalline structure The atoms in minerals are arranged in regular, repeated, geometric patterns that result in the formation of a crystal. A crystal is a solid in which the atoms are arranged in repeating patterns. Solids with specific compositions Minerals are solids and therefore have definite shapes and volumes. What is a mineral? Copyright © McGraw-Hill Education

Identifying Minerals Geologists identify minerals using tests based on a mineral’s physical and chemical properties: crystal form, luster, hardness, cleavage, fracture, streak, color, specific gravity, texture, density, and special properties. What is a mineral? Copyright © McGraw-Hill Education

There are two types of luster—metallic luster and nonmetallic luster. Identifying Minerals Luster The way that a mineral reflects light from its surface is called luster. There are two types of luster—metallic luster and nonmetallic luster. What is a mineral? Copyright © McGraw-Hill Education

Hardness is a measure of how easily a mineral can be scratched. Identifying Minerals Hardness Hardness is a measure of how easily a mineral can be scratched. German geologist Friedrich Mohs developed a scale by which an unknown mineral’s hardness can be compared to the known hardness of ten easily recognized minerals that, with the exception of diamond, are readily found in nature. What is a mineral? Copyright © McGraw-Hill Education

Identifying Minerals Cleavage and fracture A mineral that splits relatively easily and evenly along one or more planes of weak atomic bonds is said to have cleavage. Minerals that break with rough, arclike, or jagged edges because of their tightly bonded atoms are said to have fracture. What is a mineral? Copyright © McGraw-Hill Education

Streak is the color of a mineral when it is broken up and powdered. Identifying Minerals Streak Streak is the color of a mineral when it is broken up and powdered. The streak test, which typically involves rubbing the mineral against an unglazed porcelain plate, is most useful in identifying metallic minerals. It can be used only on minerals that are softer than the porcelain plate. What is a mineral? Copyright © McGraw-Hill Education

Color is one of the most noticeable characteristics of a mineral. Identifying Minerals Color Color is one of the most noticeable characteristics of a mineral. It is also one of the least reliable clues Density and specific gravity Two minerals of the same size may have different weights due to a difference in density. Density reflects the atomic mass and structure of a mineral. What is a mineral? Copyright © McGraw-Hill Education

Mineral Groups Silicates Minerals that contain silicon and oxygen, and usually one or more other elements, are known as silicates. The basic building block of the silicates is the silicon- oxygen tetrahedron. A tetrahedron is a three-dimensional shape that resembles a pyramid. Types of Minerals Copyright © McGraw-Hill Education

Oxides are compounds of oxygen and a metal, such as hematite (Fe2O3). Mineral Groups Carbonates Carbonates are minerals composed of one or more metallic elements and the carbonate ion CO32–. Magma is less dense than the surrounding solid rock, so it can rise upward into the cooler layers of Earth’s interior, where it cools and crystallizes. Oxides Oxides are compounds of oxygen and a metal, such as hematite (Fe2O3). Types of Minerals Copyright © McGraw-Hill Education

Mineral Groups Other groups Sulfides are compounds of sulfur and one or more elements, such as pyrite (FeS2). Sulfates are compounds of elements with the sulfate ion (SO42–), such as anhydrite (CaSO4). Halides are made up of chloride or fluoride along with calcium, sodium, or potassium, such as halite (NaCl). Native elements are made up of one element only, such as silver (Ag). Types of Minerals Copyright © McGraw-Hill Education