46 terms

8th Grade Rock and Mineral Flashcards

Flashcards for rocks and minerals. This is for 8th grade standards in science. There is vocab then questions.
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Sedimentary Rock
A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together.
Metamorphic Rock
A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions.
Igneous Rock
Rock that forms when magma cools and solidifies.
Texture
The look and feel of a rock's surface, determined by the size, shape, and pattern of a rock's grains.
Grains
The particles of minerals or other rocks that give a rock its texture
Foliated
Term used to describe metamorphic rocks whose grains are arranged in parallel layers or bands.
Non Foliated
The metamorphic rock texture in which mineral grains are not arranged in planes or bands rather in blocky crystal shapes.
Sediment
Loose materials, such as rock fragments,mineral grains, and the remains of once-living plants and animals, that have been moved by wind, water, ice, or gravity.
Weathering
The chemical and physical processes that break down rock at Earth's surface.
Erosion
The process by which wind, water, ice, or gravity transports soil and sediment from one location to another.
Compaction
The process by which sediments are pressed together under their own weight.
Cementation
The process by which dissolved minerals crystalize and glue particles of sediment together into one mass.
Magma
A molten mixture of rock-forming substances, gases, and water from the mantle.
Lava
Liquid magma that reaches the surface.
Extrusive Rock
Igneous rock that forms from lava on Earth's surface.
Intrusive Rock
Igneous rock that forms when magma hardens beneath Earth's surface.
Mineral
A naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition.
Naturally Occuring
A substance that must be formed by processed in the natural world.
Inorganic
Not formed from living things or the remains of living things.
Solid
Of definite shape and volume.
Crystal Structure
The particles of a mineral line up in a pattern that repeats over and over again.
Chemical Composition
What a substance is made up of at the basic chemical level.
Ways to Identify a Mineral
Luster
Streak
Hardness
Color
Density
Crystal System
Cleavage and Fracture
Special Properties
Luster
The way a mineral reflects light
Streak
The color of a mineral's powder.
Hardness
A measure of the ability of a mineral to resist scratching.
Mohs Hardness Scale
A scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals.
Color
The hue of the mineral. This is easily observed and can be a good starting point for determining a mineral but not a reliable test.
Density
The amount of matter in a given space. Each mineral has its own density. Solved by D=M/V.
Crystal System
The way atoms are arranged in symmetry of the crystals. Each mineral has its own crystal structure.
Cleavage and Fracture
Cleavage- broken with flat edges
Fracture-broken with an irregular edge
Special Properties
Some minerals have special properties:
Fluorescene
Magnetic
Radioactive
Conductive
Coarse Grained
Large crystals; easy to see in texture, intrusively formed.
Fine Grained
Texture of extrusive rocks with crystals that are invisible to the naked eye.
Clastic Rock
Sedimentary rock that forms when rock fragments are squeezed together under high pressure.
What is the hardest known mineral?
Diamond
What is the least hardest known mineral?
Talc
List the five characteristics of all minerals.
Naturally Occuring
Inorganic
Solid
Crystal Structure
Chemical Composition
How and in what order are sedimentary rocks formed?
In order:
Weathering/Erosion
Deposition
Compaction
Cementation
Why do intrusive rocks have course grains?
They are formed far underground so they cool slowly, giving more time for the grains to grow.
Why do extrusive rocks have fine grains?
They are formed at the surface, giving less time for the grains to cool.
How can you tell if a rock is organic?
If it has fossils in it.
What is the rock cycle?
The process that rocks go through continuously.
List three types of sedimentary rocks.
Here are some. Sandstone, limestone, and shale.
What is the law of superposition?
A rule saying that if a sedimentary's layers are horizontal, the one on the bottom is the oldest and the one on the top is the youngest.
What is the law of cross cutting relationships?
A rule stating that a geological feature must be younger then the geological feature it cuts through.
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