What are minerals? Think about the last time you walked on dirt.

What Are Minerals?

Chapter 7 Lesson 1Part 1

ByDesign Science, 6th Grade

What are minerals? Think about the last

time you walked on dirt.



What color was it?



What color was it? You have learned that

Earth’s crust is made of minerals and rocks.

Minerals A mineral is a solid, inorganic, natural

material with a certain structure and composition.

Minerals A mineral is a solid, inorganic, natural

material with a certain structure and composition.

Minerals are the same throughout

their composition.

MineralsCharacteristics

Minerals are solid.


Minerals are solid. Minerals are inorganic. This means that

they were never alive or part of anything that was alive. Graphite is made of carbon but was never

alive.


Minerals are solid. Minerals are inorganic. This means that

they were never alive or part of anything that was alive. Graphite is made of carbon but was never

alive. Minerals form in nature.


Minerals are solid. Minerals are inorganic. This means that they were

never alive or part of anything that was alive. Graphite is made of carbon but was never alive.

Minerals form in nature. Minerals have a specific chemical make-up, or

composition. For example, the formula for halite (table

salt) is NaCl. So one molecule of halite is always made of one atom of sodium (Na) and one atom of chlorine (Cl).


Minerals have a definite structure. A mineral’s structure depends on the atoms that make up the mineral and how the atoms combine. Diamond and graphite are both made only of

carbon (C). However, the carbon atoms in diamond are arranged in a different structure than the carbon atoms in graphite.

MineralsNot all minerals can be

identified by color. However, some minerals,

such as sulfur, have characteristic colors.

What other properties of sulfur can you see in this

picture?

MineralsNot all minerals can be

identified by color. However, some minerals,

such as sulfur, have characteristic colors.

What other properties of sulfur can you see in this

picture?Luster, Shininess,

Cleavage, Clean Sides

Minerals:Properties of

Minerals Each type of mineral has certain

characteristics or properties.


Minerals Each type of mineral has certain

characteristics or properties. Different properties

are the result of the chemical compositions and physical structure of each mineral.


Minerals Color is likely the first property that you

might observe.


Minerals Color is likely the first property that you

might observe. Some minerals are always the

same color, such as gold.


Minerals Luster is a property that describes the way

a mineral reflects light.



a mineral reflects light. A mineral with metallic luster is shiny, like a

polished metal. Silver and pyrite have

metallic luster.



a mineral reflects light. Nonmetallic minerals do not have a

shiny luster.



a mineral reflects light. Nonmetallic minerals do not have a

shiny luster. The surface of talc resembles

the surface of a pearl, so talc’s luster is described as pearly.



a mineral reflects light. Quartz has a glassy luster.



a mineral reflects light. Quartz has a glassy luster. Because one form of the

mineral hematite looks like an earthen clay pot, its luster is described as earthy.


Minerals Streak is the color of a

mineral in its powdered form.




A streak test is done by dragging a mineral across an unglazed, porcelain title called a streak plate.




A streak test is done by dragging a mineral across an unglazed, porcelain title called a streak plate.

This causes the part of the mineral being dragged to break down into a powder.


Minerals Streak is the color of a mineral in its

powdered form. Minerals with metallic luster produce dark-

colored streaks.




colored streaks. Minerals with nonmetallic luster are usually

produce either colorless or very light streaks.




colored streaks. Minerals with nonmetallic luster are usually

produce either colorless or very light streaks.

Minerals that are harder than the streak plate show no streak at all.

Properties of Minerals:Hardness

Another mineral property is hardness.


Another mineral property is hardness. Hardness is the resistance of a mineral to

being scratched.


Another mineral property is hardness. Hardness is the resistance of a mineral to

being scratched. A mineralogist named Friedrich Mohs

developed a scale that ranks the hardness of certain minerals.


Minerals and objects with

higher numbers on the scale will

scratch minerals and objects with

lower numbers on the scale.

Properties of Minerals:

Cleavage & Fracture Atoms are arranged differently in different

minerals.


Cleavage & Fracture Atoms are arranged differently in different

minerals.

These arrangements cause minerals to break in different ways.


Cleavage & Fracture Minerals that break along

smooth planes have cleavage.



smooth planes have cleavage. Graphite is a mineral that has

cleavage in only one direction.




cleavage in only one direction. This causes it to cleave, or

break, into thin sheets.





break, into thin sheets. Minerals that break along

rough, uneven surfaces have fracture.





break, into thin sheets. Minerals that break along rough,

uneven surfaces have fracture. Quartz is one mineral that

fractures.

Properties of Minerals

Other Properties In addition to color, luster, streak, hardness,

and cleavage or fracture, many minerals have unique properties.




The mineral magnetite, for example, is magnetic.





Halite tastes salty.





Halite tastes salty. Gold does not rust.


Other Properties The mineral calcite has several unique

properties. It fuzzes when it contacts an acid. It also has a property called double

refraction, which causes light shining through it to split into two rays.

What are minerals? Think about the last time you walked on dirt.

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