Arsenic

It's advisable to handle arsenic carefully to avoid generating dust and wash hands thoroughly afterward. When cutting or polishing arsenic, wear a dust mask to prevent inhaling heavy metal particles. Store arsenic in a sealed container in a well-ventilated area, away from children and pets. For those involved in crystal healing, never put it in your mouth.

Arsenic comprises about 1.5 ppm (0.00015%) of the Earth's crust, and is the 53rd most abundant element. Typical background concentrations of arsenic do not exceed 3 ng/m in the atmosphere; 100 mg/kg in soil; and 10 μg/L in freshwater. Minerals with the formula MAsS and MAs2 (M = Fe, Ni, Co) are the dominant commercial sources of arsenic, together with realgar (an arsenic sulfide mineral) and native (elemental) arsenic. An illustrative mineral is arsenopyrite (FeAsS), which is structurally related to iron pyrite. Many minor As-containing minerals are known. Arsenic also occurs in various organic forms in the environment. In 2014, China was the top producer of white arsenic with almost 70% world share, followed by Morocco, Russia, and Belgium, according to the British Geological Survey and the United States Geological Survey. Most arsenic refinement operations in the US and Europe have closed over environmental concerns. Arsenic is found in the smelter dust from copper, gold, and lead smelters, and is recovered primarily from copper refinement dust. On roasting arsenopyrite in air, arsenic sublimes as arsenic(III) oxide leaving iron oxides, while roasting without air results in the production of gray arsenic. Further purification from sulfur and other chalcogens is achieved by sublimation in vacuum, in a hydrogen atmosphere, or by distillation from molten lead-arsenic mixture.

Commercially, the most important use for arsenic is as a lead alloy, which is then used in car batteries and the manufacturing of some kinds of electronic equipment. This highly toxic material used to be used in paint and makeup before it was known to be dangerous.