Stannite The name comes from the Latin for tin: "stannum". It was first described in 1797 for an occurrence in Wheal Rock, St. Agnes, Cornwall, England. Stannite Stannite is a mineral, a sulfide of copper, iron, and tin. The chemical formula CuFeSnS. Zinc commonly occurs with the iron and trace germanium may be present. Stannite is used as an ore of tin, consisting of approximately 28% tin, 13% iron, 30% copper, 30% sulfur by mass. It is found in tin-bearing, hydrothermal vein deposits occurring with chalcopyrite, sphalerite, tetrahedrite, arsenopyrite, pyrite, cassiterite, and wolframite. It is also known as "bell metal ore"
Ore condition condition ensures "R" is an essential submodule of "D". Lastly, there is even an example of a domain in a division ring which satisfies "neither" Ore condition (see examples below). Another natural question is: "When is a subring of a division ring right Ore?" One characterization is that a subring "R" of a division ring "D" is a right Ore domain if and only if "D" is a flat left "R"-module . A different, stronger version of the Ore conditions is usually given for the case where "R" is not a domain, namely that there should be a common multiple