Gold costs were about $317 per troy ounce in 2007, but these can vary widely depending on mining type and ore quality; global mine production amounted to 2,471.1 tonnes. After initial production, gold is often subsequently refined industrially by the Wohlwill process which is based on electrolysis or by the Miller process, that is chlorination in the melt. The Wohlwill process results in higher purity, but is more complex and is only applied in small-scale installations. Other methods of assaying and purifying smaller amounts of gold include parting and inquartation as well as cupellation, or refining methods based on the dissolution
Purity and Danger contexts. What is regarded as dirt in a given society is any matter considered out of place. (Douglas took this lead from William James.) She attempted to clarify the differences between the sacred, the clean and the unclean in different societies and times. But this does not entail judging religions as pessimistic or optimistic in their understanding of purity or dirt—e.g., as dirt-affirming or otherwise. Through a complex and sophisticated reading of ritual, religion, and lifestyle, Douglas challenged Western ideas of pollution, making clear how the context and social history is essential. As an example of this approach, Douglas first