Regents Earth Science – Unit 10: Minerals and Rocks Minerals A mineral is any: 1. naturally occurring 2. inorganic 3. solid, with a 4. definite chemical composition, and a 5. crystal structure Examples: 1. naturally occurring: quartz, pyrite • cement is not a mineral - man made 2. inorganic: not formed from living things • coal is not a mineral - comes from plants 3. solid: have definite size/volume and shape • oil is not a mineral - liquid 4. chemical composition: ex.: quartz = SiO 2 5. crystal structure: atoms in geometric patterns • ex.: quartz - silicon tetrahedron Minerals are classified into different groups based on their composition/structure: • groups include: native elements, oxides, carbonates, halides, sulfides, and silicates • ex.: native elements = silver, gold, graphite (C) oxides = hematite, magnetite carbonates = calcite, dolomite halides = halite, flourite sulfides = pyrite, galena silicates = quartz, feldspar, olivene Types of Silicate Minerals: • Silicate minerals (largest group) are made from a structure called a Silicon Tetrahedron:
14
Embed
ES class notes Unit 10 - rocks and minerals · PDF fileRegents Earth Science –Unit 10: Minerals and Rocks Minerals A mineral is any: 1. naturally occurring 2. inorganic 3. solid,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Regents Earth Science – Unit 10: Minerals and RocksMinerals
A mineral is any:
1. naturally occurring
2. inorganic
3. solid, with a
4. definite chemical composition, and a
5. crystal structure
Examples:
1. naturally occurring: quartz, pyrite
• cement is not a mineral - man made
2. inorganic: not formed from living things
• coal is not a mineral - comes from plants
3. solid: have definite size/volume and shape
• oil is not a mineral - liquid
4. chemical composition: ex.: quartz = SiO25. crystal structure: atoms in geometric patterns
• ex.: quartz - silicon tetrahedronMinerals are classified into different groups based on their composition/structure:
• groups include: native elements, oxides, carbonates, halides, sulfides, and silicates
• ex.: native elements = silver, gold, graphite (C)
oxides = hematite, magnetite
carbonates = calcite, dolomite
halides = halite, flourite
sulfides = pyrite, galena
silicates = quartz, feldspar, olivene
Types of Silicate Minerals:
• Silicate minerals (largest group) are made from a structure called a Silicon Tetrahedron:
1. isolated tetrahedron - show fracture
Minerals
2. chain tetrahedron - cleavage, splinter
3. sheet tetrahedron - cleave in flat sheets
4. network tetrahedron - concoidal fracture
Formation of Minerals:
1. from cooling lava/magma
2. precipitate from solution
• water saturated with dissolved minerals evaporates - minerals are left behind)
Mineral Identification
Minerals are identified on their physical and/or chemical properties:
Physical Properties:
1. Color
2. Streak
3. Luster
4. Hardness
5. Breakage (Cleavage/Fracture)
6. Density (Specific Gravity)
Physical Properties1. Color - not dependable for identifying most minerals
• most minerals can have many colors
ex. hematite - black, gray, silver, brown, red
• very few common minerals have only one color
ex. sulfur - yellow
• many minerals are the same color
ex. black - magnetite, hematite, mica, hornblende sulfur hematite
2. Streak - color of the powder when a mineral is rubbed on a streak plate
• very reliable for identification
• streak for a mineral is always the same color (no matter the color of the mineral)
ex.: hematite - reddish-brown streak
3. Luster - the way a mineral shines/reflects light
a. Metallic - shines like a metal - galena, pyrite
b. Non-metallic - does not look like a metal:
• pearly - mica
• glassy - quartz, halite
• dull/earthy - hematite (red ochre)
• waxy - talc
• brilliant - diamond
Physical Properties
4. Hardness - how easily a mineral is scratched
• use fingernail and glass plate:
– fingernail has a hardness of 2.5
– glass has a hardness of 5.5
Moh's Hardness Scale
5. Breakage
• Cleavage - mineral breaks along smooth, flat surfaces (due to internal structure of atoms)
• the atomic structure of minerals gives minerals a characteristic crystal shape