Rocks Flashcards
What are the 8 ways of classifying minerals?
Colour, streak, lustre, hardness, crystal structure, cleavage, magnetism, and reaction with certain chemicals
Why would and wouldn’t you use colour to identify a mineral?
Would because it’s easy to determine and wouldn’t because some minerals are the same colour but doesn’t mean it’s the same mineral
What is Mohs hardness scale?
A scale that includes minerals from softest to hardest and what could scratch it
What is magma?
Hot molten rock under Earth’s surface
What is igneous rock?
Rock that forms from the hardening of liquid magma
What is intrusive?
When magma is cooled underground
What is lava?
Magma that’s forced out onto Earth’s surface
What is extrusive?
When igneous rock is formed by lava cooling on Earth’s surface
What is sediment?
Rock particles that include clay, mud, sand, gravel, and boulders
What is sedimentary rock?
Rock that is formed by breaking down, depositing, compacting, and cementing of sediment
What is metamorphic rock?
Igneous or sedimentary rock that’s properties have changed because they were buried so deeply that the heat and pressure changed the properties
How are minerals different from rocks?
Minerals are usually found mixed together to form rocks
Do bigger crystals cool quickly or slowly?
Slowly
What are fossils?
Rock-like casts, impressions, or actual remains of organisms that were covered by sediment when they died before they decomposed
How are fossils formed?
By an organism falling into mud, quicksand, a landslide of sediment; or blowing volcanic ash. The organism then becomes sedimentary rock. Minerals in water eventually replace minerals in the organism and voila!
What is a fossil record?
The data we have from fossils
What is the geological time scale?
A time scale using fossils to determine the changes of life on Earth
Why are there very few fossils?
Because most dead organisms decay or are eaten by scavengers and soft tissues don’t fossilize well
Why aren’t fossils found in metamorphic rock?
Because metamorphic rocks can’t survive the pressure of fossilizing
What is weathering?
The process that slowly breaks down natural minerals like rocks and boulders in to smaller pieces
What is mechanical weathering?
Weathering caused by a physical force
What is ice wedging?
When water falls into the cracks of rocks, freezes, expands, and pressures the rock to widen
What is chemical weathering?
When chemicals break down or weaken rock materials
What is biological weathering?
When living things cause mechanical or chemical weathering
