Geosphere, Minerals, and Rocks

native element

A non-silicate mineral group of minerals that contain only 1 element.

oxides

A non-silicate mineral group of minerals that contain oxygen and a metal in the compound.

silicates

The most common mineral group that makes up ~90% of the crust and is made up of compounds that contain silicon and oxygen.

sulfides

A non-silicate group of minerals that contains sulfur and a metal as part of the compound.

carbonates

A non-silicate group of minerals that contain carbon and oxygen in the compound CO3

Physical properties

Characteristics of minerals that help with identification created by the mineral's unique combination of chemical composition and arrangement of atoms.

Streak

Color of a mineral's powder left behind on a streak plate. One of the physical properties useful in mineral identification. Especially for metallic minerals.

cleavage

the tendency of a mineral to break along flat surfaces due to planes of weak bonding. One of the physical properties useful in mineral identification.

Fracture

When minerals break in directions other than along cleavage surfaces (i.e. not along flat planes).

color

the color of a mineral sample recognized by inspection. One of the physical properties useful in mineral identification.

impurity

Foreign material, such as elemental additions, within a mineral's structure that are not part of its integral structure. Impurities are often responsible for color changes.

Luster

The way a mineral reflects light. Two main types are metallic and non-metallic. One of the physical properties useful in mineral identification.

hardness

resistance of a mineral to scratching. Described on Moh's hardness scale from 1-10, with one being the softest.

element

A pure substance that cannot be broken down into other substances by chemical or physical means. Symbols will be a capital letter or capital letter plus 1 lowercase letter on the periodic table of elements. Some minerals are elements.

Oxygen

most abundant element in the earth's crust (~47%)

Silicon

2nd most common element in the earth's crust (~28%)

Compound

A combination of elements

Inorganic

not formed from living things or the remains of living things. Was never alive.

Sedimentary Rock

A type of rock that typically forms when sediment goes through the 4 part process of deposition, burial, compaction, and cementation. Can also chemically precipitate directly from water.

Metamorphic Rock

A type of rock that forms from an existing rock that is changed by heat and/or pressure.

Igneous Rock

a type of rock that forms from the solidification of molten magma or lava.

Naturally-occurring

Not made by humans. One of the 5 criteria of a mineral.

mineral

a naturally occurring, inorganic, solid that possesses a definite chemical composition and structure which gives it a unique set of physical properties

Quartz

The most common mineral in the crust. It is made of the two most abundant chemical elements on Earth: oxygen and silicon. It is part of the silicate mineral group and has a chemical formula of SiO2.

Feldspar

Part of the silicate mineral group that is one of the most common minerals in the crust along with quartz. We have seen plagioclase and orthoclase (potassium) feldspar samples.

rock

naturally occuring solid that usually contains more than 1 mineral.

aggregate

rock composed of a collection of minerals, particles, or smaller pieces

bedding planes

The sedimentary rock texture with relatively flat surfaces along which the rocks tend to separate or break

foliation

The metamorphic rock texture in which mineral grains are arranged in planes or bands.

Granite

A usually light colored igneous rock that is found in continental crust

Basalt

A dark, igneous rock with a fine texture, found in oceanic crust

Pahoehoe

A hot, fast-moving type of lava that hardens to form smooth, ropelike coils

aa

lava that hardens into rough, jagged rocks with a crumbly texture

Deposition

The geological process in which sediments, soil and rocks are added to a landform or land mass. Step 1 of 4

Burial

A process in making sedimentary rock where a layer of sediments is buried under subsequent layers. Step 2 of 4

Compaction

Part of the formation of sedimentary rocks. When sediments are deeply buried, the pressure of overlying layers squashes the grains together more tightly. Step 3 of 4

Cementation

A process in making sedimentary rock in which new minerals form between sediments to bind them all together. Step 4 of 4

Pressure Process

When existing minerals change deep in the earth with the application of extreme heat and pressure (without melting).

Precipitation Process

The method of forming minerals from water with dissolved atoms/ions in it that either a) becomes supersaturated (ex: hydrothermal) OR evaporates (ex: salt flats).

Magma Process

As magma cools, atoms within it slow down and bond into crystalline solids/minerals. The longer it takes for the magma to cool, the larger the crystals grow.

Magma

molten (hot liquid) rock located below the surface

Lava

molten (hot liquid) rock that has reached the surface

Pyroclastic

Fragments of rock erupted by a volcano

Solidification

The cooling of magma or lava to form igneous rock.

Melting

The process of changing a rock back into magma by applying heat.

Heat and/or Pressure

Comes from magma, tectonic plate movement or deep burial. Process that creates metamorphic rocks.

Crust

The thin, solid, brittle, outermost layer of the Earth above the mantle

Mantle

The layer of hot, solid material between Earth's crust and core. It is a solid, but can flow like a liquid.

outer core

the liquid layer of the Earth's core that lies beneath the mantle and surrounds the inner core

inner core

A dense sphere of solid iron and nickel at the center of Earth.

Sediments

broken pieces of rock, categorized by size

gravel

Sediment with a diameter between 2 mm and 64 mm.

sand

Sediment with a diameter between 0.05 mm and 2 mm.

silt

Sediment with a diameter between 0.002 mm and 0.05 mm.

Weathering

The breaking down of rocks and other materials on the Earth's surface.

Erosion

The process by which wind, water, ice, or gravity transports soil sediment, and rock from one location to another

Weathering and Erosion

The breaking down and removal of rocks and other materials on the Earth's surface. These processes create sediment from any type of rock.