Rocks and Minerals

Cleavage

The tendency of a mineral to break along flat surfaces is called cleavage. Cleavage in science refers to how minerals break along smooth, flat planes where the bonds are weaker.

Crystal

A solid of ions or atoms arranged in an orderly three-dimensional pattern. Crystal. A crystal is a structure where particles are arranged in a repeating, organized pattern.

Density

An object's mass per unit volume. Density. Density is how much stuff is packed into a certain space.

Fracture

An irregular break in a mineral. Fracture. In science, a fracture is when a material, like a rock or bone, breaks or cracks under stress.

Gem

A rare, valuable mineral. Gem. A gem is a naturally occurring mineral known for its beauty and durability, often used in jewelry.

Hardness

A minerals resistance to scratching. Hardness. Hardness measures how difficult it is to scratch a material.

Lava

Molten rock that reaches the Earth's surface. Lava. Lava is hot, liquid rock that flows from volcanoes.

Luster

The way a mineral's surface reflects light. Luster. Luster is the appearance or quality of light reflected from the surface of a mineral.

Magma

Molten rock beneath the Earth's surface. Magma. Magma is hot, liquid rock found under the Earth's crust.

Mineral

A natural inorganic solid with definite chemical composition and structure. mineral. A mineral is a naturally occurring substance made of one or more elements with a specific crystal form.

Ore

A rock that contains enough mineral to be mined for profit. ore. Ore is a type of rock that contains valuable minerals that can be extracted and sold.

Silicate

A mineral with silicon, oxygen, and other elements. Silicate. Silicates are minerals made from silicon and oxygen, forming the building blocks of rocks.

Streak

A color of a mineral in its powdered form streak. Streak is the color left behind when a mineral is scratched across a porcelain tile, helping to identify it.