the three major categories of rocks. the rock forming minerals the most abundant minerals in the...
TRANSCRIPT
![Page 1: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/1.jpg)
The three major categories of rocks
![Page 2: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/2.jpg)
The Rock Forming minerals
• The most abundant minerals in the earth’s crust and the most common in rocks are:-
• Quartz
• Feldspar
• Mica
• Pyroxene
![Page 3: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/3.jpg)
Igneous Rocks
• Formed by the cooling and solidification of melted rock (molten silicate liquid) called magma or lava.
![Page 4: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/4.jpg)
![Page 5: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/5.jpg)
![Page 6: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/6.jpg)
![Page 7: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/7.jpg)
Classification of igneous rocks
Texture – crystal size
All large crystals
- Produced by relatively slow cooling deep underground.
- Found in intrusive igneous rocks.
![Page 8: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/8.jpg)
Classification of igneous rocks
Crystal size
- Small crystals and/or glass
- Produced by rapid cooling, usually at or near the earth’s surface.
Typical of extrusive rocks.
Occasionally in intrusive rocks close to the surface.
![Page 9: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/9.jpg)
![Page 10: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/10.jpg)
Classification of igneous rocks
Other texturesBubbleswhich are trapped in igneous rocks are
called vesicles. E.g Pumice.Broken fragmentsIf there is enough gas, expanding bubbles
cause lava to break into fragments explosively. E.g. volcanic ash and pumice.
![Page 11: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/11.jpg)
![Page 12: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/12.jpg)
![Page 13: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/13.jpg)
Sediments and Sedimentary rock
There are different types of sediment
1. Clastic sediments (also called detrital sediment).
2. Chemical sediment
3. Biochemical sediment
![Page 14: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/14.jpg)
Some examples
![Page 15: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/15.jpg)
Textures of Sedimentary rock
Clastic sediment
Maximum grain size – fine, medium and coarse.
Grain shape – angular and rounded.
Sorting – well or poorly sorted.
![Page 16: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/16.jpg)
Well and poorly sorted sediment
![Page 17: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/17.jpg)
Clastic rocks
By texture
• Course and rounded – conglomerate
• Course and angular – breccia
• Medium - sandstone
• Fine – siltstone, mudstone, claystone or shale.
![Page 18: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/18.jpg)
![Page 19: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/19.jpg)
Sandstone by composition
• Pure quartz sand – quartz sandstone
• Sand and fine matrix – graywacke sandstone.
• Sand with 20% rock fragments – lithic sandstone.
![Page 20: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/20.jpg)
![Page 21: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/21.jpg)
Chemical and biochemical Sedimentary Rocks
Calcite – Limestone
Plant remains – Coal or peat
Silica – Chert
Halite – Rock Salt
Gypsum – Rock Gypsum
![Page 22: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/22.jpg)
![Page 23: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/23.jpg)
![Page 24: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/24.jpg)
Sedimentary structures
• Layering
• Ripples
• Cross-bedding
• Mud craks
• Burrows and tracks (fossils)
![Page 25: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/25.jpg)
![Page 26: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/26.jpg)
![Page 27: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/27.jpg)
![Page 28: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/28.jpg)
Metamorphism
• Includes process which change the minerals and texture of rock without melting it
![Page 29: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/29.jpg)
Causes of metamorphism
Pressure
Different minerals are stable at different pressures.
Changing the pressure can change the types of minerals in rocks.
![Page 30: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/30.jpg)
Causes of metamorphism
Temperature
Different minerals are stable at different temperatures.
Changing the temperature can cause the types of minerals present in the rock to change.
![Page 31: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/31.jpg)
Causes of metamorphism
Hydorthermal fluids
Usually water and/or CO2 plus dissolved materials.
Can change the chemical composition of rocks by adding or removing materials.
Many important ore deposits have been formed by metamorphic deposits.
![Page 32: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/32.jpg)
![Page 33: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/33.jpg)
Other types of metamorphism
• Deformation – along fault lines
• Hydrothermal – associated with igneous intrusions along ocean ridges
• Burial – caused by deep burial.
• Shock – caused by sudden high pressures caused during impacts
![Page 34: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/34.jpg)
![Page 35: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/35.jpg)
Metamorphic rocks
Composition and texture are used to decribe these rocks, just like the previous ones.
![Page 36: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/36.jpg)
Metamorphic rocks
Texture
Foliated rocks and this refers to the preferred orientation of the mineral grains in rocks as a result of directed pressure.
Non-foliated rocks have no mineral orientation.
![Page 37: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/37.jpg)
![Page 38: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/38.jpg)
Foliated metamorphic rocks
Slate
Schist
Gneiss
Phyllite
![Page 39: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/39.jpg)
![Page 40: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/40.jpg)
![Page 41: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/41.jpg)
Non-foliated metamorphic rocks
• Quartzite
• Marble
• Skarn
• Hornfels
![Page 42: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/42.jpg)
![Page 43: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/43.jpg)
![Page 44: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/44.jpg)
![Page 45: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/45.jpg)
Sedimentary Rocks
Metamorphic Rocks
The Rock Cycle
Sediments
Magma
![Page 46: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/46.jpg)
Sediments
SedimentaryRock
Metamorphic Rock
IgneousRock
Magma
Cooling
Melting
Heat and pressure
Uplift
UpliftUplift
Heat and pressure
Burial andlithification
Deposition in oceans andon continents
Weathering and erosion
![Page 47: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/47.jpg)
![Page 48: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/48.jpg)
Minerals
Make up the lithosphere, mantle and the core.
• Over 4000 are known.
• Minerals are used
extensively by humans.
• Minerals record information about the
processes that formed them.
![Page 49: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/49.jpg)
![Page 50: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/50.jpg)
![Page 51: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/51.jpg)
Minerals the building blocks of rocks
• Definition of a mineral.Homogenous (uniform throughout)
Naturally occurring (no synthetics)
Inorganic (no biological stuff)
Solid (no liquid or gas)
Ordered internal molecular structure
Definite chemical composition
![Page 52: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/52.jpg)
Rocks
• An aggregate of minerals
• Most rocks have
more than one
Mineral.
• Some rocks are mono mineralic
![Page 53: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/53.jpg)
Granite is an igneous rock made up of several minerals
Quartz FeldsparHornblende
![Page 54: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/54.jpg)
Crystals
• A single continuous mineral with crystal faces.
• The faces indicate growth inan open space.• Crystals of the same mineralshave similar faces, which reflectthe ordered atomicarrangement.
![Page 55: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/55.jpg)
Polymorphs
These are minerals with the same chemical composition.
But different crystalline structures
Diamond and graphite are polymorphs of (C).
![Page 56: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/56.jpg)
![Page 57: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/57.jpg)
![Page 58: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/58.jpg)
Mineral Physical Properties
The characteristics determined by your 5 senses.
• Used to ID minerals• Depend upon…
Chemical Composition
Crystal Structure
![Page 59: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/59.jpg)
Physical Properties
• Crystal Form• Crystal Habit• Luster• Color• Streak• Hardness• Cleavage• Fracture• Specific Gravity
![Page 60: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/60.jpg)
Crystal Form
• Ideal shape displayed by crystal faces. These are variable and depend on the chemicals involved.
![Page 61: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/61.jpg)
Crystal Form
• Minerals may exhibit a range
of crystal face development• Euhedral – Well-developed• Anhedral – No visible crystal faces.
Usually from growth in a confined space.• Subhedral – Between the two.
![Page 62: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/62.jpg)
Crystal Form
Crystals need an open space to grow, or they take on a different form.
Quartz crystals from an open and closed space.
![Page 63: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/63.jpg)
Luster
Appearance in reflected light.Two categories
MetallicNon-metallic
Vitreous (glassy)SilkyResinousEarthy (dull)Adamantine (brilliant)
![Page 64: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/64.jpg)
Colour
• Often unreliable for mineral ID.
• May vary due to impurity elements.
• Many gemstones are brightly colored.
![Page 65: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/65.jpg)
Streak
Color of a mineral when scratched (crushed) on an unglazed porcelain plate.
![Page 66: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/66.jpg)
Hardness
• Resistance of a mineral to abrasion or scratching.
• All minerals are compared to a standard scale
• called the Mohs scale of hardness.
![Page 67: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/67.jpg)
Moh’s scale of hardness10 Diamond
9 Corundum
8 Topaz
7 Quartz
6 Feldspar
5 Apatite Glass
4 Flourite
3 Calcite Coin
2 Gypsum Fingernail
1 Talc
Hardest
Softest
![Page 68: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/68.jpg)
Cleavage
• Tendency to break along planes of lattice weakness.
• Cleavage produces flat, shiny surfaces.• Described by resulting geometric shapes.• Number of planes• Angles between adjacent planes• Be careful to discriminate from crystal form
![Page 69: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/69.jpg)
Cleavage
• Cleavage in one direction
![Page 70: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/70.jpg)
More Cleavage
• 2 directions at 90º
• 2 directions NOT at 90º
• Example: Amphibole Example: Amphibole
• Example: Potassium Feldspar Example: Potassium Feldspar
• Cleavage
•
![Page 71: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/71.jpg)
More Cleavage
• 3 directions at 90º
• 2 directions NOT at 90º
![Page 72: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/72.jpg)
Conchoidal Fracture
• Some minerals lack planes of weakness.
• Molecular bonds are equally strong in all directions. They don’t cleave; they fracture.
Conchoidal fracture - curved surfaces, sharp edges.
![Page 73: The three major categories of rocks. The Rock Forming minerals The most abundant minerals in the earth’s crust and the most common in rocks are:- Quartz](https://reader033.vdocuments.mx/reader033/viewer/2022052603/5697bf9c1a28abf838c93005/html5/thumbnails/73.jpg)
Specific Gravity
• Ratio of the weight of a mineral to the weight
of an equal volume of water• Average crustal value is 2.7 (quartz)• Average mantle value is 3.3 (olivine)
SG is reflected in “heft” – how heavy the mineral feels.• Galena – Heavy Feldspar - Light