Rock-It - Unit 3 - Minerals, Rock Types, & Rock Cycle

mineral

solid that is naturally occurring, inorganic, and has crystal structure, and a definite chemical composition

crystal structure

the atoms in a crystal are arranged in an orderly, repeating pattern

crystallization

the process by which atoms form a solid with an orderly, repeating pattern; can occur from magma or from water

density

the amount of mass in a given volume; used to identify minerals

Mohs hardness scale

from 1-10, talc = 1, diamond = 10

streak

the color of a mineral's powder

luster

the way a minerals surface reflects light (e.g. metallic, glassy, earthy, pearly)

cleavage

the splitting of a mineral along smooth, flat surfaces

fracture

occurs with minerals that break along rough or irregular surfaces; may be conchoidal (shell-shaped)

HCl

reacts with minerals made of calcium carbonate (calcite, limestone, marble)

rock

naturally occurring solid mixture composed of minerals, smaller rock fragments, organic matter, or glass

grains

individual particles in a rock

rock texture

refers to grain size and how the grains are arranged

igneous rock

one of the three main rock types, formed from the cooling and hardening of magma. Sometimes the magma cools deep within the earth, and other times it erupts onto the earth's surface from volcanoes (in this case, it is called lava). Examples: basalt, obsidian

magma

hot, molten rock found deep inside the earth. When it reaches the surface, it is called lava

melting

the process that turns any rock into magma. Melting a rock requires extremely high temperatures, which only occur far beneath the earth's surface.

cooling

the process that hardens magma and turns it into igneous rock.

crystallization

the process of elements forming an organized structure

basalt

dark-colored intrusive igneous rock; most common rock type in the earth's crust and makes up most of the ocean floor

granite

light-colored intrusive igneous rock made up mainly of feldspar, quartz, and mica

volcano

an opening in the earth's surface that allows hot magma, ash, and gases to escape from deep below the surface. When magma reaches the surface through a volcano, it is called lava. When lava cools, it forms extrusive igneous rock.

extrusive rock

igneous rock formed from lava that erupted onto Earth's surface

intrusive rock

igneous rock that forms when magma hardens beneath Earth's surface.

sedimentary rock

one of the three main rock types, formed from particles of sand, shells, pebbles, and other fragments of material. Together, all these particles are called sediment. Gradually, the sediment accumulates in layers and over a long period of time hardens into rock. Generally, sedimentary rock is fairly soft and may break apart or crumble easily. You can often see sand, pebbles, or stones in the rock, and it is usually the only type that contains fossils. Examples: conglomerate, sandstone, limestone

lithification

the process through which sediment turns into rock

sediment

loose pieces of minerals and rocks.

compacting

a process that turns sediment into sedimentary rock. Over time, sediment accumulates in oceans, lakes, and valleys, eventually building up in layers and weighing down the material underneath. This weight presses the sediment particles together.

cementing

a process that turns sediment into sedimentary rock. Water passing through the spaces in between the particles helps to "glue" them together.

fossils

imprints of leaves, shells, insects, or other items left in sedimentary rock.

weathering

the process by which rocks are worn down by wind and water, creating sediment.

erosion

the process by which soil, sediment, and small pieces of rock are carried away from their original locations and transferred elsewhere by the actions of wind, water, ice, or living organisms.

deposition

process in which sediment is laid down in new locations

sedimentation

the process of settling or being deposited as a sediment.

metamorphic rock

one of the three main rock types, formed deep within the earth, where rock material is subjected to intense heat and pressure (squeezing). The rocks that result from these processes often have ribbonlike layers and may have shiny crystals on their surface, formed by minerals growing slowly over time. Examples: Marble, Gneiss

heat and pressure

the process that occurs under the earth's surface and turns any kind of rock into metamorphic rock.

deformation

this process occurs when rocks in the crust are compressed or stretched. The forces needed to do this act over millions of years - this is a very slow process!

foliation

results when pressures cause flat minerals to line up, giving the rock a layered appearance.

The Rock Cycle

the recurring series of events that rocks undergo, over time, that transforms them from one type to another.

uplift

The process of areas of rock moving slowly upwards, pushed up by pressure of the rocks forming underneath.

increasing heat & pressure

shale > slate > phyllite > schist > gneiss (see picture on p.482)