The Geological Society of London’s Online interactive resource The Rock Cycle, with the Rock Cycle Animation, shows how surface and deep Earth processes produce the rocks we stand on and use to build our homes. Also find a glossary, demonstrations/experiments and extensive background information about the rock cycle.
Break minerals to observe their cleavage or fracture. How a mineral breaks depends upon the mineral’s structure. Cleavage is an easily demonstrated property of minerals such as calcite, halite, and mica.
Students take a small piece of unexpanded vermiculite, holding it with tongs or long tweezers, and insert it into the ﬂame of a propane torch. The vermiculite expands rapidly to many times its original thickness.
Exposure to ultraviolet light causes changes in minerals. One of the lesser-known phenomena is tenebrescence, in which a mineral actually changes color upon exposure to ultraviolet light (this is not the same as ﬂuorescence). Using an ultraviolet light, you can give a mineral a reversible “suntan.”
Everyone loves ﬁreworks and students often wonder how ﬁreworks get their rich colors. Using the flame test, students can produce their own colored flames and learn about ﬁreworks, minerals, and their common elements.