- a loose rock larger than 256 millimeters (10 inches)
C
cleavage
- the shape that occurs when a rock is split cleanly
cobble
- loose particles of rock or mineral that are the size of gravel larger than pebbles, but smaller than boulders
conglomerate
- sedimentary rock made of rounded pebbles held in together with a matrix
continent
- one of seven main land masses on the earth
core
- the huge mass in the very center of the Earth made mostly of iron and nickel. It is divided into an outer core and inner core
crust
- the solid outermost part of the Earth. The crust is all the land you see and the land on the ocean bottom
crystal
- a solid in which the particles are arranged in a pattern to make shapes with flat surfaces
crystal shape
- crystals often form regular geometric shapes (cubes, hexagonals, etc.) which can aid in their identification
E
earthquake
- sudden release of energy built up in an area on the crust or upper mantle sudden ground motion or vibration of the Earth
element
- substances which cannot be broken down into other substances
epicenter
- the location on the surface of the earth just above the focus of an earthquake
erosion
- the movement of weathered rocks and soil
extrusive rock
- volcanic rock which solidifies on the surface of the earth rather than inside of the earth
F
fault
- a crack in the earth's crust where earthquakes often occur
focus
- the location under the earth's surface where an earthquake occurs
formation
- a body of rock with special that allow geologists to map, describe, and name it
fossil
- something that has lasted from a living thing that died long ago. They can be body parts, that have turned into stone or animal tracks
G
geologist
- a scientist who studies geology
geology
- the science of the rocks and minerals that compose the earth, of its structure, and of its history
gravel
- all sedimentary particles larger than 2 millimeters is called gravel. Gravel is subdivided into pebbles, cobbles, and boulders
H
hardness
- A measure of the ease with which a smooth surface of a mineral can be scratched. See Mohs scale
I
igneous rock
- rock formed when molten rock has cooled and solidified
intrusive rock
- igneous rock that forms when magma cools below the Earth's surface
L
lava
- molten rock that flows out onto the Earth's surface
luster
- how light reflects off of a rock or mineral
M
magma
- molten rock that is located beneath the Earth's surface
magnetism
- the naturally-occurring electrical field in some rocks
mantle
- the thick layer of very hot, melted rock between the crust and the core of the Earth
matrix
- fine-grained material surrounding larger grains in a sedimentary rock
metamorphic rock
- rocks that are changed from sedimentary, igneous or other metamorphic rocks by intense pressure and heat
mineral
- a non-living, solid material with particles arranged in a repeating pattern called a crystal. A mineral is usually a combination of 2 or more elements. A mineral cannot be broken down into any other substance
Mohs scale
- a scale used to measure the hardness of a mineral
molten
- melted
P
pebbles
- Loose particles of rock or mineral that range in size from 2 - 64 millimeters in diameter. Pebbles are the smallest type of gravel
R
Richter Scale
- a measurement scale for identifying the amount of energy released by an earthquake
rock
- a combination of 2 or more minerals which have been joined either by heat, temperature, pressure, or chemical changes
rock cycle
- the process in which igneous, sedimentary, and metamorphic rocks are changed over time
S
sand
- loose particles of rock or mineral that range in size from 0.0625 to 2.0 millimeters in diameter
sediment
- material that comes from the weathering of rock or from from fragments of plants and animals that settles to the bottom of rivers, lakes, and seas
sedimentary rock
- rock formed from rock types that have weathered, cemented, and/or squeezed together
sedimentation
- the process of breaking up rocks into smaller fine pieces that sink to the bottom of rivers, lakes, and seas
seismologist
- a scientist who studies the waves created by an earthquake
shale
- soft rock formed from layers of mud soil
strata
- layers, or bands, in rocks
streak
- the color that shows when a mineral is scratched on the surface
T
tectonic plates
- huge sections of the earth's crust that float on the mantle
V
vent
- An opening in the earth's surface
volcanic
- igneous rock that forms when magma cools on the Earth's surface
W
weathering
- the breaking of rocks by water, snow, ice, wind, chemicals, gravity or plant roots
