From The Town Of Bedrock, Its a Place Right Out Of History

A MINERAL DEFINED the solid portion of the earth is composed of rocks rocks are composed of minerals All minerals are defined by the following:

Naturally occurring: mother nature makes minerals…not us! Inorganic: made of things that are not living and never will be

living! Solid: hard and breakable Homogeneous: the same throughout Definite chemical composition: unique combination of elements Crystalline structure: repeating pattern of atoms that creates

crystals

A MINERAL IDENTIFIED There are 6 traits you can

test to help you correctly identify a mineral sample

1. Color2. Hardness

3. Streak4. Cleavage/Fracture

5. Luster6. Unique characteristics

COLOR Color is okay to look at

initially, but you can not base your decision only on that one trait

Why? Trace elements can vary the external color.

If we only looked at color, we would not identify it correctly.

These are both diamonds

CAN YOU SCRATCH IT? When you try to scratch a

mineral, you are testing its hardness

If it can be scratched, then it is softer than the object you used to scratch it

If it cannot be scratched, then it is harder than the object you used to scratch it

Common minerals and their hardness are ranked on Moh’s Hardness Scale, listed from the softest to the hardest

FIELD HARDNESS CHART page 106

WE HAVE A STREAKER!!

The streak of a mineral is the mineral in its powdered form

Minerals will only have a streak if they are softer than the streak plate (which has a hardness of 7)

If the mineral has a metal in its chemical formula, it will usually leave a streak

The streak color will not always be the same color as the mineral…so don’t assume!

I NEED A BREAK!!! Cleavage and

fracture are two terms used to describe how a mineral breaks

Cleavage means it breaks with smooth, flat surfaces

Fracture means the mineral breaks along jagged surfaces

OH, HOW IT SHINES! How a mineral shines

describes its luster If it shines like a metal, it

has metallic luster If it does not shine like a

metal, it has nonmetallic luster1. Dull2. Glassy3. Earthy4. Pearly5. Waxy

UNIQUE CHARACTERISTICS Magnetism

(magnetite) Double refraction,

double image (calcite) Fizzes when acid is

placed on it (calcite) Fluorescence (glows

under a black light) Olfactory (sulfur)

smell Specific gravity: one

of the best tests to help you identify a mineral !