Many things in the material world are taken for granted, not realizing or appreciating their presence or value. Construction materials that make up the material world around us come into this unconscious, “invisible” category. Though you see buildings, roads, footpaths and bridges every day, it is almost certain you have never thought about what the materials are, what they are made of, or where they come from. The vast bulk of our built environment is formed from raw materials won from the earth by the extractive industries. Without the raw materials with which to build houses, hospitals, schools, factories, roads, etc., life would certainly be more basic and less comfortable than we presently experience.