| A | B |
|---|
| acid rain | precipitation of relatively high acidity that is formed when airborne oxides of sulfur and nitrogen combine with moisture in the atmosphere |
| calcium carbonate | a chemical compound forming the principal constituent of certain rocks and minerals such as limestone and calcite |
| conglomerate | a rock made of mineral and rock fragments |
| crystal | a solid substance in which the particles are arranged in an orderly, repeatable pattern |
| crystallization | the process by which crystals are formed |
| cubic | a crystal form characterized by three equal axes at right angles to each other |
| evaporation | the conversion of a substance from a liquid to a gaseous state |
| fossil | the remains, impressions, or other evidence of living things preserved in rock |
| gemstone | a precious or semiprecious mineral used in jewelry and industry |
| hardness | the resistance of the surface of a mineral to scratching by another substance |
| hexagonal | a crystal form characterized by three equal lateral axes intersected at 60 degrees and a vertical axis of variable length at right angles |
