Inadvertent exposure to a variety of minerals, whether it be via inhalation, absorption through the skin, or ingestion with food or drink, can elicit a toxic response. The first line of defense is offered by the gastrointestinal system: vomiting and diarrhea. Through vomiting, contaminated food is expelled. Through diarrhea, malabsorption as well as excretion of a recirculated mineral is facilitated, reducing the intestinal exposure and subsequent uptake of the mineral. No general discussion of trace minerals would be complete without mention of mineral interactions. Numerous antagonisms and synergisms have been reported. This should be expected as one realizes that many of the trace minerals have more than one charged state and that living cells have preferences with respect to the states. Iron, element 26 in the periodic table, is the fourth most prevalent mineral in the earth’s crust. It has an atomic weight of 56. Neolithic man learned to mine iron and to forge tools from iron.