Calamine brass a mixture of the virtually indistinguishable zinc ores smithsonite and hemimorphite) as the zinc component of brass. The resulting brasses, produced by heating a mixture of copper and calamine to a high temperature for several hours (allowing zinc vapor to distill from the ores and permeate the metallic copper), contained a significant amount of slag material resulting from the non-zinc components of calamine. The use of ore rather than metallic zinc also made it difficult to accurately produce the desired final proportion of copper to zinc. This process is known as cementation. Calamine brass was produced using proportions of two-sevenths
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