1. Minerals

2. Facts about Minerals A naturally occurring homogeneous solid
Minerals can be elements
Minerals can be salts
Minerals can be silicates
The study of minerals is called mineralogy

3. Physical Properties of Minerals
Classifying minerals can be very complicated and expensive
However there are also time-effective and affordable ways
There are 8 main properties that can be used to classify minerals

4. Crystal Structure
-- This refers to the arrangement of the atoms.
X-ray diffraction is used to see these arrangements.
Crystal structures can range from large and granular, to layered sheets, to microscopic crystals

5. Hardness
-- The hardness of a mineral is calculated using the Moh’s Hardness Scale.
This categorizes the physical hardness of the mineral and ranges from 1 to 10.
We will look at this in greater detail later

6. Lustre
-- Refers to the way the mineral’s surface interacts to the light and can range from dull to glassy. There are three major categories of lustre:
Metallic (Galena)
Sub-Metallic (Hematite)
Non-Metallic (Sulphur)

7. Colour
-- What it looks like to the naked eye.
Streak
-- Refers to the colour of the powder a mineral leaves after rubbing it on an unglazed porcelain plate

8. -- Describes the way a mineral may split apart
Cleavage
-- Describes the way a mineral may split apart
Fracture
-- Describes the way a mineral breaks when broken contrary to their natural cleavage planes
Specific Gravity
-- This is another name for density

9. Moh’s Hardness Scale
Devised by Friedrich Mohs
Scratching tools: 
fingernail (2.2)
copper penny (3.5)
pocket knife or common nail (5.2)
piece of glass (5.5)
steel file or concrete nail (7.5)

10. Notes for testing:
Each mineral can scratch minerals with lower hardness ratings.
Each mineral can scratch itself.
Don’t press hard, normal scratching should do.
Weathered surfaces are softer.

11. Corners or edges of crystals are softer.
Small pieces seem softer than large pieces.
When you scratch, take a close look at the scratch line - which often looks white. Is it really a scratch or is it a powder line made from the tool you used because it was softer than the item you were trying to scratch?