Minerals and Rocks Crossword Puzzle

QUESTIONS LIST:

• intrusive rock : (also called plutonic rock) igneous rock that forms when magma cools and hardens while still underground
• extrusive rock : (also called volcanic rock) rock that is formed when magma reaches the surface, is extruded out of the earth as lava, then cools and hardens
• porphyritic rock : type of igneous rock that is formed when magma cools first slowly and then quickly, giving the rock a mixed texture
• concretion : hard round structure that forms when minerals settle out of water and crystallize around a sand grain or other mineral fragment
• amorphous : describes rocks that are formed when magma cools very rapidly and no crystals form
• stratum : horizontal rock layer that has a different type of rock layer above it
• conglomerate rock : sedimentary rock that consists of smooth pebbles embedded in hardened sand or clay
• evaporite : chemical sediment that forms from the evaporation of water
• salt dome : halite deposit that occurs deep underground as huge, cylindrical structures
• coal seam : layered formation of coal usually buried in other sedimentary rock such as sandstone or shale
• overburden : in surface mining, the upper layers of the ground stripped away to expose the coal beneath it
• metamorphism : change of one type of rock into a new type of rock