Calamine brass Calamine brass Calamine brass is brass produced by a particular alloying technique using the zinc ore calamine directly, rather than first refining it to metallic zinc. Direct zinc smelting appears to have been unknown in Europe until the mid-18th century, even though the alloyed calamine brass was in use for centuries, and metallic zinc was produced directly via reducing-atmosphere smelting in India and China from the 12th century CE onwards. Brass is an alloy of copper and zinc and, when it was first developed, methods for producing metallic zinc were unknown. Metallurgists wishing to produce brass thus used calamine (actually
Ore condition right order in "D" includes the condition that "D" must consist entirely of elements of the form "rs". Any domain satisfying one of the Ore conditions can be considered a subring of a division ring, however this does not automatically mean "R" is a left order in "D", since it is possible "D" has an element which is not of the form "s""r". Thus it is possible for "R" to be a right-not-left Ore domain. Intuitively, the condition that all elements of "D" be of the form "rs" says that "R" is a "big" "R"-submodule of "D". In fact the