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Baker 7th grade science Baker 7th grade science

Baker 7th grade science - PowerPoint Presentation

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Baker 7th grade science - PPT Presentation

Mineral ID How to identify a mineral by its properties Baker 7th grade science Today you will learn Which mineral properties are most important in identification How mineral are identified by their properties ID: 228888

7th mineral science grade mineral 7th grade science baker color streak property minerals break properties breaks cleavage density amp

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Slide1

Baker 7th grade science

Mineral ID

How to identify a mineral by its propertiesSlide2

Baker 7th grade science

Today you will learn

Which mineral properties are most important in identification.How mineral are identified by their properties.Slide3

Baker 7th grade science

A mineral’s appearance helps identify it.

In order to identify a mineral, you need to observe it properties – characteristics that help identify it.

There are 5 main properties that we use to identify. There are many minor properties that can also help id a mineral.Slide4

Baker 7th grade science

Mineral Property #1 Color & Streak

Color is the first thing someone notices when they view a mineral.

Color is also one of the big reasons that attract people to minerals.

Generally speaking, color is not a good property to be used in the identification of minerals. It is usually the first property to confuse a novice collector into making an incorrect identification.

Many minerals have different colors and some minerals' colors are identical to other minerals' colors.Slide5

Baker 7th grade scienceSlide6

Baker 7th grade science

Mineral Property #1 Color & Streak

Streak is closely related to

color

,

but is a different property because the color of the mineral may be different than the color of the streak.

Streak is actually

the color of the powder of a mineral.

It is called streak because the proper way to test for streak is to rub a mineral across a tile of white unglazed porcelain and to examine the color of the "streak" left behind. Slide7

Baker 7th grade scienceSlide8

Baker 7th grade science

Mineral Property #1 Color & Streak

Pyrite

(known as "

Fool's Gold

") is always brassy yellow when found in crystals, even broken crystals, of any size; but when powdered, produces a black streak.

Gold's

streak, by the way, is yellow!

Hematite's

streak is blood-red

Galena's

streak is lead graySlide9

Baker 7th grade science

Mineral Property # 2Luster

A mineral’s luster is the way in which light reflects from the surface. The two major types of luster are metallic & nonmetallic.Slide10

Baker 7th grade scienceSlide11

Baker 7th grade science

Mineral Property # 2Luster

Some other ways to describe luster are

Dull

- just a non-reflective surface of any kind

Earthy

- the look of dirt or dried mud

Fibrous

- the look of fibers

Greasy

- the look of grease

Gumdrop

- the look a sucked on hard candy

Metallic

- the look of metals

Pearly

- the look of a pearl Pitchy - the look of tar Resinous - the look of resins such as dried glue or chewing gum Silky - the look of silk, similar to fibrous but more compact

Submetallic

- a poor metallic luster, opaque but reflecting little light

Vitreous

- the most common luster, it simply means the look of glass

Waxy

- the look of wax Slide12

Baker 7th grade science

Quick Check

Get out your whiteboard and quickly answer the following:What is the first thing someone notices about a mineral?What do we call the color of the powdered mineral?

Which is more reliable: streak or color?Slide13

Baker 7th grade science

Mineral Property # 3How a mineral breaks

When a mineral breaks it does so either by

fracturing

or by

cleaving

.

Cleavage is the tendency of a mineral to break along flat surfaces.

Crystal cleavage is a smooth break producing what appears to be a flat crystal face.

Fracture is the tendency of a mineral to break into irregular pieces.Slide14

Baker 7th grade scienceSlide15

Baker 7th grade science

Mineral Property # 3How a mineral breaks

When a mineral breaks it does so either by

fracturing

or by

cleaving

.

Cleavage is the tendency of a mineral to break along flat surfaces.

Crystal cleavage is a smooth break producing what appears to be a flat crystal face.

Fracture is the tendency of a mineral to break into irregular pieces.Slide16

Baker 7th grade scienceSlide17

Baker 7th grade science

Mineral Property #4Hardness

A mineral’s hardness is its resistance to being scratched. A scale known as the Moh’s scale is often useSlide18

Baker 7th grade scienceSlide19

Baker 7th grade science

Mohs ScaleSlide20

Baker 7th grade science

Mineral Property #5Density

Each mineral has a specific density.Density is the mass of a given space or in scientific terms the mass per unit of volume.

For example, if you have two minerals of the same size one might be heavier than the other. The galena will be three times heavier than the same size of quartz.Slide21

Baker 7th grade scienceSlide22

Baker 7th grade science

Mineral Property #5Density

Geologists measure density by the following:First they use a balance to determine the mass of a sample.

Second, they place the mineral in water to see how much water it displaces.

The volume of displace water = the volume of the sample

Third they use the following formula:

Density = Mass/VolumeSlide23

Baker 7th grade science

Brain Check

Get out your whiteboard and quickly answer the following:If you break a mineral and it breaks into cubes, is it fracture or cleavage? Why?

If you break a mineral with a hammer and it falls apart into a million different pieces, is it fracture or cleavage? Why?

Name three things you can scratch talc with.

What is the formula for density?Slide24

Baker 7th grade science

Some minerals have specific properties

Fluorescence: some minerals glow when exposed to ultraviolet lightMagnetic: Some minerals are attracted to magnets

Acid: Some minerals react with acid by bubblingSlide25

Baker 7th grade science

SLCDFHSome Llamas Climb Down Funny Hills

S

treak

Powdered Color

L

uster

How shiny

C

leavage

Breaks in sheets or blocks

D

ensity

How much mass in a given volume

F

racture

Just crumbles & breaksHardnessCan be scratched by