caseb rocks minerals

Properties of Minerals Geologists use characteristics to tell one mineral from another... Mineral Properties we will studyCleavage Streak... –Nonmetallic: does not look like polished me

Properties of

Minerals

Geologists use characteristics to tell one

mineral from another

Mineral Properties we will study

Cleavage Streak

• Refers to the way light reflects

from the surface of the mineral

• There are two types of luster,

–Metallic: looks like polished metal –Nonmetallic: does not look like

polished metal

Pyrite has metallic luster

Quartz has nonmetallic luster

These are not all of the tools geologists use,

but it will work for our experiment

Gypsum is soft, it can be scratched by a fingernail.

Calcite is soft, but a little harder

because it cannot be scratched by a fingernail, but it can be scratched by

a penny

Fluorite is harder It can be scratched by a nail, but not a penny

or fingernail

Diamonds are the hardest mineral,

so it scratches every mineral

• Not all minerals have cleavage

• Some minerals split easily along a

flat surface

• The number of lines that are

created when a mineral is split will

be the number of cleavage lines

Mica has cleavage in one

direction

It breaks along one line

Feldspar has two lines of cleavage It breaks along two

lines

• Red chalk on a chalk board makes

red marks White chalk makes white marks

• Not all minerals work this way When

some minerals are scratched along a ceramic streak plate, it creates a

different color

Pyrite or “Fool’s Gold”

across a streak plate,

it has a black or dark

green streak

much money, while

gold is worth a lot

They look alike, so

miners call it fool’s

grey, but its streak is

red

named hematite

because it looked like

it was bleeding when

it was taken across a

streak plate

One mineral property we will

not use…

COLOR

A mineral can be many different

colors Below is Mica

Many minerals can be the same color Below are

gold colored minerals Which one is gold?

The answer…

None of them were

real gold

Just like with people…

Outside color does not tell you much about the important

characteristics