Minerals Flashcards
Lithosphere
A general term that encompasses the entire solid Earth realm. In plate tectonics, it refers to the solid, brittle outer part of the Earth; includes the crust and mantle.
Atmosphere
The air surrounding the Earth. It is made of gases such as oxygen, nitrogen, hydrogen, etc
Hydrosphere
The water part of the Earth. Includes oceans, groundwater, and water held in the atmosphere. The Earth is covered by .75 water and .25 land mass
What are the four major zones of the Earth’s lithosphere?
Crust
Mantle
Outer core
Inner core
Crust
The thinnest zone of Earth’s lithosphere; the outermost solid shell or layer of earth. 3-40 km thick; composed largely of silicate minerals. The continents compose the crust and are about 40 km thick. The ocean crust is thinner (3-8km)
Mantle
Plastic deformable layer under the crust in the Earth’s lithosphere. Approx. 1800 miles thick. Made of dense rock. Contains iron.
Innter and outer core
Combined thickness of the two zones is 2100 miles
Both consist or iron and nickel
Outer core: molten
Inner core: solid, about 7400F, high pressure (100 million pounds/in^2)
Regolith
All the loose eroded material at the Earth’s surface. The layer of mineral particles covering bedrock, e.g., soil, weathered rock.
Minerals
Crystalline, inorganic, naturally occurring substances with definite physical and chemical properties and chemical composition. They consist of chemical elements or compounds, e.g., graphite, pyrite, quartz, olivene
Element
A substance consisting of only one type of atom. There are more than 100 elements that occur in nature like gold, silver, oxygen, and chlorine.
Compound
A substance consisting of two or more elements chemically combined, eg salt (sodium and chlorine), water (hydrogen and oxygen)
How are minerals identified?
Chemical and physical properties.
Example-
Diamonds are very hard
Water is liquid at room temp and boils at 100C
Physical properties (name 13)
Properties that can be seen or felt, like color, hardness, boiling and melting points, luster, malleability, ductility, conductivity, solubility, streak, cleavage, fracture, crystal shape, specific grav
Chemical properties
Properties that describe how a substance reacts with others like sodium burning in air and water or iron rusting
How do you measure a mineral’s hardness?
Hardness is the resistance of a mineral to abrasion or scratching. We can use a scale that incorporates the hardness of ordinary objects (like copper penny, glass, knife blade, fingernail). We can observe how easily a substance scratches OTHER materials (diamond can scratch glass) or how easily it is scratched by other minerals
What is the Moh’s scale of hardness?
A method for comparing the relative hardness of minerals. Values from 1 (softest) to 10 (hardest)
List the ten minerals that identify the values of the M. Scale of Hardness.
- Talc
- Gypsum (2.5 = fingernail)
- Calcite, Penny
- Fluorite
- Apatite
- Fedspar, glass, knife blade, orthoclase
- Quartz
- Topaz
- Corumdum
- Diamond
Streak
The color of a mineral when it is ground into powder. Rub a mineral against streak plate (dull piece of ceramic tile) to see streak.
Streak is ___ for metallic minerals and ___ for non-metallic minerals
Dark grey or black
Colorless or lighter than mineral
Cleavage
Because of the weaknesses in atomic structure, some minerals break along predictable planes of weakness called cleavage planes (like how mica splits only in one direction in very thin sheets or feldspar cleaves in two directions)
Fracture
Some minerals have no cleavage zones. They split with rough, irregular surfaces (like quartz)
Crystal
Regular arrangement of atoms in a mineral. A definite pattern is repeated through the substance. It is the external expression of a mineral that reflects the orderly internal arrangement of atoms, like how quartz crystals are 6 side prisms and pyrite and salt are cubic
Unit cell
Smallest unit that repeats in crystal
How is a crystal formed?
When molten rock cools slowly or water with dissolved mineral evaporates slowly, its atoms have the time to form regular patterns. This occurs any time a mineral is permitted to form without space restrictions.
