Minerals

Mineral Definition

1. A mineral is naturally occurring… 2. A mineral is inorganic (was never alive)… 3. A mineral is solid…

4. A mineral is crystalline (made of crystals) 5. A mineral has a definite chemical composition (composition doesn’t change) 6. A mineral has definite physical properties

There are over 3000 minerals! Common Minerals There are over 3000 minerals! Only about 30 are commonly found in the Earth’s crust

The Rock Forming Minerals The 30 (or so) common minerals that form most rocks on the Earth’s crust

Natural or synthetic (man made) Living or non-living Review: A mineral is…(choose one answer) Natural or synthetic (man made) Living or non-living Solid, liquid or gas Definite or variable properties There are about 3000 or 30 minerals that form most rocks Is ice a mineral?

Based on SEVERAL PROPERTIES Identifying Minerals Based on SEVERAL PROPERTIES Each property tells only part of the mineral’s identity All properties caused by the INTERNAL ARRANGEMENT of ATOMS in the MINERAL

Luster is the way a mineral shines or reflects light Two Types: ESRT Metallic Non-Metallic

2 minerals with metallic luster 2 minerals with non-metallic luster ESRT Review: ESRT p 16 2 minerals with metallic luster 2 minerals with non-metallic luster A mineral that can have either metallic or non-metallic luster What causes a mineral to have either type of luster?

Hardness: resistance to being scratched Based on MOH’S Scale of hardness Hardness of 1: softest (least resistant) Hardness of 10: hardest (most resistant)

Fingernail: hardness of 2.5 MOH’s Scale Fingernail: hardness of 2.5 If mineral scratches fingernail, it has a greater hardness (>2.5) Penny: hardness of 3.0 A mineral that scratches a penny has a hardness of > 3.0

If mineral scratches a nail, it has a greater hardness (>5.5) MOH’s Scale Nail: Hardness of 5.5 If mineral scratches a nail, it has a greater hardness (>5.5) Glass: hardness of 6.5 A mineral that scratches glass has a hardness of > 6.5

What causes a mineral’s hardness? ESRT Review: ESRT p 16 2 minerals that will not scratch your fingernail 2 minerals with will scratch a penny but NOT a nail (hardness between 3 and 5) Two minerals that will scratch glass What causes a mineral’s hardness?

Cleavage: if a mineral breaks evenly When a mineral has flat surfaces… Cleavage and Fracture Cleavage: if a mineral breaks evenly When a mineral has flat surfaces… Or regular shapes

Fracture: if a mineral breaks unevenly Cleavage and Fracture Fracture: if a mineral breaks unevenly When a mineral has an irregular shape

2 minerals with cleavage 2 minerals with fracture ESRT Review: ESRT p 16 2 minerals with cleavage 2 minerals with fracture What causes a mineral to have either cleavage of fracture?

But the NOT VERY useful! WHY? Many minerals have similar colors Caused by the type of atoms in the mineral Easy to observe! But the NOT VERY useful! WHY? Many minerals have similar colors

Some minerals have many colors NOT VERY useful! WHY? Some minerals have many colors

2 minerals that can be green 2 minerals that can be white ESRT Review: ESRT p 16 2 minerals that can be green 2 minerals that can be white What causes a mineral’s color?

Distinguishing Characteristics Unique properties that identify minerals STREAK: The color of a mineral in powdered form Not always the same as color! This mineral has a brown streak

Distinguishing Characteristics Unique properties that identify minerals Can also include how a mineral looks, feels or tastes! This mineral Reacts in acid This mineral is magnetic

2 minerals that bubble in acid 2 minerals that have greasy feel ESRT Review: ESRT p 16 2 minerals that bubble in acid 2 minerals that have greasy feel What causes a mineral’s distinguishing characteristics?

Chemical Composition The chemical elements a mineral is made from Metallic Minerals – contain metal elements Pyrite contains IRON

Most Minerals (over 60%) contain Silicon and Oxygen Chemical Composition Most Minerals (over 60%) contain Silicon and Oxygen These minerals are called SILICATES Silicates contains Si and O arranged in pyramid shape called silica tetrahedron Chemical formula SiO4

2 minerals that are silicates ESRT Review: ESRT p 16 2 minerals that are silicates 2 non-metallic minerals are not silicates Two metallic minerals What creates a mineral’s chemical composition?

Review: Use notes and ESRT What type of luster in mineral A? What type of luster in mineral B? Which mineral has cleavage? Which mineral has fracture? A B

Review: Use notes and ESRT What is the hardness of a mineral that will scratch a nail but not scratch glass? What is the hardness of a mineral that will not scratch penny? Which mineral has a red-brown streak? One non-metallic mineral containing silica tetrahedra. The number of rock forming minerals A very hard, red mineral found in NYS ESRT

crystal shapes Crystal shape can be a useful property to identify minerals if the minerals have had the time and space to form crystals. Most mineral grains that are found in rocks, lack the room to grow.

Pure gold can have a specific gravity as high as 19.3! Specific gravity tells you how many times as dense as water the mineral is. Pure gold can have a specific gravity as high as 19.3!

acid test Calcite is calcium carbonate, CaCO3. If a drop of weak hydrochloric acid is placed on calcite, the acid bubbles as carbon dioxide is released.

Other Special Properties Magnetic Malleable Radioactive Flourescence Taste

Can you think of a mineral that might be shaped or hammered? Malleable or Ductile Minerals that can be hammered thin or shaped are said to show these properties. Can you think of a mineral that might be shaped or hammered?

Gold would be a perfect example!

p9 p10 p14 p17 p20 p23 p26 p27 p28

Magnetic Some minerals that contain Iron, are magnetic and can be picked up by a magnet.

This is the state of glowing while under a ultraviolet light. Fluorescence This is the state of glowing while under a ultraviolet light. Some minerals even glow once the light is turned off!

Some minerals, such as this uraninite, are radioactive. They give off subatomic particles that will activate a Geiger counter.

Halite (rock salt) can be identified by its taste. This practice is not recommended!