#separator:tab #html:false #tags column:4 Rock A solid natural material made of one or more minerals earth-rocks Igneous rock Rock formed when melted rock cools and hardens earth-rocks Sedimentary rock Rock formed when sediments are pressed and cemented together earth-rocks Metamorphic rock Rock changed by heat and pressure earth-rocks Magma Melted rock beneath the surface earth-rocks Lava Melted rock that has reached the surface earth-rocks Intrusive igneous rock Igneous rock that cooled slowly underground, with large crystals earth-rocks Extrusive igneous rock Igneous rock that cooled quickly at the surface, with small crystals earth-rocks Granite A light-colored intrusive igneous rock with visible crystals earth-rocks Basalt A dark, fine-grained extrusive igneous rock earth-rocks Obsidian Natural volcanic glass earth-rocks Pumice A light igneous rock full of holes that can float earth-rocks Rhyolite An extrusive rock with the same makeup as granite earth-rocks Gabbro A dark intrusive igneous rock earth-rocks Sandstone Sedimentary rock made of cemented sand grains earth-rocks Limestone Sedimentary rock made mostly of calcium carbonate earth-rocks Shale Sedimentary rock made of compacted clay and mud earth-rocks Conglomerate Sedimentary rock with rounded pebbles cemented in it earth-rocks Breccia Sedimentary rock with angular fragments cemented together earth-rocks Coal A sedimentary rock made from ancient plants earth-rocks Chalk A soft, white form of limestone earth-rocks Marble Metamorphic rock formed from limestone earth-rocks Slate Metamorphic rock formed from shale; splits into flat sheets earth-rocks Quartzite Metamorphic rock formed from sandstone earth-rocks Gneiss A banded metamorphic rock formed from granite or similar rocks earth-rocks Schist Metamorphic rock that shines with mica flakes earth-rocks Phyllite Metamorphic rock between slate and schist earth-rocks Weathering Breaking down of rock by wind, water, ice or plants earth-rocks Erosion Moving of weathered material from one place to another earth-rocks Deposition Dropping of sediments in a new place earth-rocks Sediment Small pieces of rock, shell or soil moved by water, wind or ice earth-rocks Compaction Pressing sediments together under weight earth-rocks Cementation Minerals gluing sediments together earth-rocks Lithification The process that turns sediment into rock earth-rocks Rock cycle The never-ending change of rocks from one type to another earth-rocks Foliated Having layers or bands, as in some metamorphic rocks earth-rocks Crystal A solid with atoms arranged in a repeating pattern earth-rocks Fossil The preserved remains or traces of ancient life earth-rocks Which rock type usually contains fossils? Sedimentary earth-rocks Strata Layers of sedimentary rock earth-rocks Law of superposition In undisturbed layers, the oldest rock is at the bottom earth-rocks Core sample A tube of rock or ice pulled from the ground for study earth-rocks Geologist A scientist who studies Earth and its rocks earth-rocks Petrologist A scientist who studies rocks earth-rocks Soil A mix of weathered rock, organic matter, water and air earth-rocks Humus Dark, rich decayed plant and animal matter in soil earth-rocks Topsoil The top soil layer, rich in nutrients earth-rocks Bedrock Solid rock beneath soil earth-rocks Clay The smallest soil particles earth-rocks Silt Soil particles of medium size earth-rocks Sand Soil particles larger than silt and smaller than gravel earth-rocks Loam A balanced soil of sand, silt and clay earth-rocks Frost wedging Water freezing in cracks and splitting rock earth-rocks Chemical weathering Rock changed by chemical reactions, like rusting earth-rocks Physical (mechanical) weathering Rock broken into smaller pieces without chemical change earth-rocks Delta Sediment fan built where a river meets a larger body of water earth-rocks Glacier A large moving mass of ice that carves the land earth-rocks Rock that forms from lava cooling Igneous earth-rocks Rock that forms from heat and pressure on other rocks Metamorphic earth-rocks Rock that forms in layers Sedimentary earth-rocks