Earth science 1.2 : Identifying minerals

IDENTIFYING MINERAL

Earth Science

Chapter 1.2

Objectives:

1. Identify seven ways to determine the identity of minerals.

2. Explain special properties of minerals.

Identifying Minerals Use Properties

Color○ Minerals display a wide variety of colors, and often the

same mineral can be found in many different colors○ usually not the best way to identify a mineral

*** All varieties of Quartz

LusterThe way a mineral reflects lightThree types of mineral luster1. Metallic – bright, reflective

2. Submetallic – dull, reflective

3. Nonmetallic - dull

glassy silky resinous waxy

pearly Earthy

StreakThe color of a mineral in powdered formCan be found by running the mineral against a

piece of unglazed porcelain called a streak platecolor of a mineral’s streak is not always the same

as the color of the mineral sample

Gold

Platinum

Copper

Cleavage and FractureDifferent types of minerals break in different

ways

1. Cleavage○ Tendency of some minerals to break along smooth, flat

surfaces

2. Fracture○ Tendency of some minerals to break unevenly along

curved or irregular surfaces

Examples of cleavageExamples of fracture

HardnessMineral’s resistance to being scratchedscientists use Mohs hardness scale

Densitymeasure of how much matter is in a

given amount of spaceDensity is a ratio of an object’s mass to

its volume

Density = 5.1 g/cm3

Density = 19.3 g/cm3

Specific Gravity : Ratio of an objects density to the density of water

Special PropertiesSome properties are particular to only a

few types of minerals