Terms

Crust

The outermost solid layer of Earth, composed mostly of silicate minerals.

Mantle

The layer beneath the crust, made of solid and partially molten rock, rich in magnesium and iron.

Core

The innermost part of Earth, composed mostly of iron and nickel.

Silica Tetrahedron

The basic building block of silicate minerals, consisting of one silicon atom bonded to four oxygen atoms.

Atom

The smallest unit of an element that retains its chemical properties.

Atomic Mass Number

The sum of protons and neutrons in an atom's nucleus.

Atomic Number

The number of protons in an atom’s nucleus, determining the element.

Atomic Weight

The weighted average mass of an element’s isotopes.

Mineral

A naturally occurring, inorganic solid with a definite chemical composition and crystalline structure.

Chain Silicate Structure

A silicate structure where silica tetrahedra are linked in chains.

Cleavage

The tendency of a mineral to break along specific planes due to its atomic structure.

Crystal Form

The external shape of a mineral that reflects its internal atomic structure.

Density

Mass per unit volume of a substance (g/cm³ for minerals).

Luster

The way a mineral reflects light, such as metallic or non-metallic.

Electron

A negatively charged subatomic particle found in atoms.

Neutron

A neutrally charged subatomic particle found in an atom's nucleus.

Proton

A positively charged subatomic particle found in an atom’s nucleus.

Igneous Rock

Rock formed from the cooling and solidification of magma or lava.

Basalt

A fine-grained, dark-colored, mafic volcanic rock.

Granite

A coarse-grained, felsic intrusive igneous rock.

Magma

Molten rock beneath Earth’s surface.

Lava

Molten rock that has erupted onto Earth’s surface.

Caldera

A large crater formed when a volcano collapses.

Cinder Cone

A small, steep-sided volcano made of volcanic debris.

Pyroclastic Flow

A fast-moving, hot cloud of volcanic ash, gas, and debris.

Chemical Weathering

The breakdown of rocks by chemical reactions.

Clastic Sedimentary Rocks

Rocks composed of fragments of pre-existing rocks that have been compacted and cemented together.

Sedimentary Structure

Features in sedimentary rocks that provide clues about past environments.

Metamorphic Grade

A measure of how much heat and pressure a rock has experienced.

Marble

A metamorphic rock formed from limestone, often used in sculptures.

Foliation

A layered or banded texture in metamorphic rocks caused by pressure.

Quartzite

A hard metamorphic rock formed from sandstone, mainly composed of quartz.