Chapter 4 - Rocks and Minerals Flashcards
rocks
solid materials composed of minerals
silicate minerals
(silicon+oxygen, SiO2) include quartz, mica, feldspar, hornblende, augite, and olivine, which are initially crystallized from magma. Quartz may also from in voids within sedimentary rocks by precipitation from aqueous solutions
intrusive igneous
igneous rock that cools and solidifies below the surface
extrusive igneous
cool above the Earth’s surface, exposed to the atmosphere or ocean; basalt is an example
calcite
main constituent of the carbonate rock limestone
calcite
predominant mineral in limestone; notable cleavage in 3 directions, creating rhombohedrons
clastic sedimentary rocks
composed of fragments of weathered rock that have been transported
metamorphism
“change of form”
contact metamorphism
occurs relatively locally, around the margins of molten rock
regional metamorphism
occurs on a larger scale and is usually associated with the pressures of mountain-building
mineral
naturally occurring, solid, inorganic substance having a specific chemical composition and a specific crystal structure
color
used in identification of a mineral
streak
the color of a mineral when it is ground to powder
luster
the way a mineral shines in reflected light
cleavage
the tendency of a mineral to break evenly along one or more bright, planar surfaces
hardness
a mineral’s resistance to scratching by another substance of known hardness
Mohs Scale of Mineral Hardness
1-10 1 Talc; 2 Gypsum; 3 Calcite; 4 Fluorite; 5 Apatite; 6 Orthoclase; 7 Quartz; 8 Topaz; 9 Corundum; 10 Diamond
density
mass per unit volume - density = mass/volumen
crystal habit
the way a mineral has grown by means of regualar addition of ions to its surfaces from a liquid solution, a gas, or molten rock
magnetism, taste, flexibility and feel
other ways to identify minerals
igneous rocks
formwhen molten rock cools and crystallizes
sedimentary rocks
formwhen sediment becomes compressed and/r cemented over time
metamorphic rocks
undergo change in form due to the action of heat, pressure, or chemical activity
plutons
very large masses of intrusive igneous rocks