Unit: Rocks Flashcards
What do Geologists look at?
mineral composition, color and texture of the rock
What does color give scientist?
provides clues to the rock’s mineral composition
What are 2 examples of color info?
granite- light colored rock having high silica
basalt-dark colored rock that is low in silica
What is a rock’s texture
look and feel of the rocks surface which is made up of the minerals or other fine rocks( grains)
What are the 3 grains?
grain size, shape, and pattern
What 3 groups to scientist classify rocks in?
sedimentary, igneous, metamorphic
How are igneous rocks formed?
created by magma or lava when it cools or crystalizes( obsidian)
How does sedimentary rocks form?
forms when rocks are broken down and joins together has rocks, plants, animals all pressed together
How is metamorphic rock formed?
forms when existing rock is changed by heat and pressure or chemical reactions
What are the 5 properties of minerals?
1.solid under normal conditions
2.naturally occurring
3.crystalline structure
4. definite chemical composition
5.inorganic substances
characteristic- color
used to identify a few minerals that have their own mineral color
characteristic- streak
color of the minerals powder
characteristic- luster
how light reflects off surface
characteristic-density
how dense it is
Characteristic hardness
how easily minerals break on surfaces
characteristic-crystal system
used to form structure of minerals
characteristic- cleavage
if a mineral breaks easily on flat surface
characteristic-fracture
when a mineral breaks apart in an irregular way
What is a geode?
rounded, hollow rock, that is often lined with mineral crystals
what is crystallization
process by which atoms are arranged to form a material with a crystal structure
crystallization of magma/lava
minerals form as hot magma-cools inside the crust or as lava hardens under the surface
crystallization of materials dissolved in water
when elements and compounds that are dissolved in water leave a solution
what is a gemstone
hard colorful mineral that is glassy in luster; one cut/polished it is called a gem
What are metals
minerals are the source of metals
what is ore
rock that contains a metal or other useful minerals that is mined and sold for a profit
What are 2 types rocks are formed?
extrusive, intrusive
what is extrusive formation
lava cools outside the ground
what is intrusive
magma cools under the surface
what is sediment
small, solid, pieces of matter that comes from rocks, animals, plants
what is foliated
metamorphic rocks that have thta have their grains organized in a parallel layer/bands
what is non-foliated
minerals grains’ are arranged randomly
