Physical Science: Chapter 22 Vocab

Cleavage

The way a mineral breaks along one or more smooth, flat planes.

Luster

The visual appearance of a mineral as it absorbs, reflects, or refracts light.

Streak

The color of the powder left by a mineral when it is rubbed across an uglazed porcelian tile.

Minerologist

An earth scientist who studies the formation, composition, and properties of minerals.

Silicates

The rock forming minerals made up of silicon-oxygen molecules either alone or in combination with one or more other elements

quartz

One of the most abundant and stable minerals in the earth's crust, made of one atom of silicon and two atoms of oxygen

Feldspar

a group of aluminum silicate minerals characterized by their hardness and distinct right-angle clevage. They are the most abundant of all rock forming minerals

Oxides

minerals that form when oxygen atoms bond with metal atoms, such as calcium, magnesium, or iron

Native Elements

Metallic and nonmetallic minerals composed of a single element in its purest uncombined form

Igneous

A type of rock formed when magma cools and crystallizes below or on the surface of the earth

Magma

Molten or liquid rock that is present below the earth's surface

Lava

molten rock that flows from vents or volcanoes on the earth's surface, also the same material solidified from cooling

Sedimentary

A type of rock formed when horizontal layers of sediment harden into solid rock at or just below the earth's surface

Weathering

The natural breakdown of solid rock into small fragments through chemical, physical, and biologic processes.

Erosion

The transport of soil and rock fragments by mass movement, running water, glacier or wind

Lithification

The set of chemical and physical processes that converts newly deposited sediment into rock.

Metamorphic rock

A type of rock formed by the squeezing and heating of rocks deep below the surface of the earth

Foliation

A distinctly layered texture found in some metamorphic rocks

Plate tectonics

A theory in geology that says the earth's crust is composed of a large, slowly moving plates.

mineral

a naturally occurring, crystalline, inorganic element or compound that possesses a fairly definite chemical composition and a distinctive set of physical properties

Mohs Scale

the degrees of hardness are represented by this scale, which runs from 1 to 10, soft to hard.

Rock

a solid cohesive natural aggrevate of one or more minerals

uniformitarianism

the principle that the same processes operate on and within the Earth today as in the past. Hence the present is considered the key to the past.

rock cycle

a series of events through which a rock changes over time, between igneous, sedimentary, and metamorphic forms

plutons

classified according to the size and shape of the intrusive bodies and according to their relationship to the surrounding rock they penetrate.

pyroclastics

(tephra) Solid material emitted by volcanoes; range in size from fine dust to large boulders

viscosity

the internal property of a substance that offers resistance to flow

caldera

a roughly circular, steep-walled depression formed as a result of the collapse of a volcanic chamber

sediment

mineral or organic matter deposited by water, air, or ice.

bedding

the stratification of sedimentary rock formations

metamorphisim

the process by which the structure and mineral content of a rock are changed while the rock remains soid

contact metamorphisim

a change in rock brought about primarily by heat rather than pressure.

shear metamorphisim

a change in rock brought about primarily by pressure rather than heat

regional metamorphisim

a change in rock over a large area, brought about by both heat and pressure

foliation

the mineral orientation characteristics of some meta-morphic rocks that results from directional pressures during transformation

hydrothermal metamorphisim

the chemical alteration of preexisting rocks by chemically reactive, hot-water solutions, which dissolve some ions from the original minerals and replace them with other ions, thus changing the mineral composition of the rock.