minerals how to identify a mineral

Physical Properties of Minerals 1.. Physical Properties of Minerals 1... Minerals with a hardness greater than “7” usually don’t create a streak on the streak plate because they are h

Minerals

A What is a mineral?

Mineral Characteristics shared by all minerals:

 1 Natural

– occurs naturally

– NOT manmade

– Chemical formula

– SiO 2 is Quartz

How will we remember this?

Mineral Characteristics shared

B Physical Properties of Minerals

 1 Color

– First impression

– Not very reliable because lots of minerals

can occur in many different colors

 Purple Amethyst

Fluorite •Clear•Blue

•Green

•Purple

Physical Properties of Minerals

 1 Color

 2 Streak

– The TRUE color of a mineral

– Color of a mineral’s powder

Minerals with a hardness greater than “7” usually don’t create a streak on the streak plate because

they are harder than the Porcelain tile (unless the

streak plate is specially made).

Physical Properties of Minerals

 1 Color

 2 Streak

 3 Hardness

– A mineral’s resistance to being scratched

– Mohs Hardness Scale from 1-10

Hardness depends on how “tightly

packed” the atoms are

Mohs Hardness Scale

Physical Properties of Minerals

“Cleav” = to split

Cleaver

Physical Properties of Minerals

Fracture

Physical Properties of Minerals

Luster

Physical Properties of Minerals: Used for Identification (I.D.)

Fluorescence

under ultraviolet,

UV light

– Continues to glow even after the

UV light has been removed

Piezoelectric (Pressure=Electricity)

D Identification Tests

 1 Hardness

 2 Streak (True Color)

 3 Acid Test

– Use hydrochloric acid

– Tests for carbonate (calcite)

Caves can form in rocks with

calcite, like here in Harrisonburg!

Acid in groundwater dissolves the calcite