| A | B |
|---|
| ore | material that contains enough of a useful metal that it can be mined and sold for profit |
| crystal | solid material with atoms arranged in an orderly, repeating pattern |
| rock cycle | model that shows the slow continuing process of rocks changing from one type to another |
| rock | solid inorganic material that is usually made up of two or more minerals |
| extrusive | igneous rocks that have small or no crystals and form when melted rock cools quickly on Earth’s surface |
| foliated | metamorphic rocks that have visible layers of minerals |
| nonfoliated | metamorphic rocks that do not have distinct layers or bands of minerals |
| intrusive | igneous rocks that usually contain large crystals and form when magma cools slowly beneath Earth’s surface |
| igneous rocks | intrusive or extrusive rock that forms when melted rock from inside Earth cools and hardens |
| gems | rare valuable mineral that can be cut and polished |
| sedimentary rocks | type of rock made from pieces of other rocks, dissolved minerals, or plant and animal matter that collect to form rock layers |
| metamorphic rocks | new rock that forms when existing rock is heated or squeezed |
| minerals | inorganic, solid materials that have crystal structure, cleavage, fracture, color, hardness, and streak |
| detrital | sedimentary rock with grains or parts from other rocks |
| organic | sedimentary rock made from plant or animal parts |
| chemical | sedimentary rock made of minerals in solution |
