| A | B | 
| mineral | a naturally occuring, inorganic solid that has a crystal structure and a definite chemical composition | 
| inorganic | not formed from living things or the remains of living things | 
| crystal | a solid in which the atoms are arranged in a pattern that repeats again and again | 
| element | a substance composed of a single kind of atom | 
| compound | a substance in which two or more elements are chemically joined | 
| mixture | two or more substances that are mixed together but not chemically combined | 
| Mohs hardness scale | a scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals | 
| streak | the color of a mineral's powder | 
| luster | the way a mineral reflects light from its surface | 
| density | the amount of mass in a given space; mass per unit volume | 
| cleavage | a mineral's ability to split easily along flat surfaces | 
| fracture | the way a mineral looks when it breaks apart ina irregular way | 
| fluorescence | the property of a mineral in which the mineral glows under ultraviolet light | 
| magma | the molten mixture of rock-forming substances, gases, and water that makes up part of Earth's mantle | 
| lava | magma that reaches the surface; also the rock formed when liquid lava hardens | 
| solution | a mixture in which one substance is dissolved in another | 
| vein | a narrow slab of a mineral that is sharply different from the surrounding rock | 
| gemstone | a hard, colorful mineral that has a brilliant or glossy luster | 
| ore | rock that contains a metal or economically useful mineral | 
| smelting | the process by which ore is melted to separate the useful metal from the other elements | 
| alloy | a solid mixture of two or more metals |