Mineral Many sulfide minerals are economically important as metal ores; examples include sphalerite (ZnS), an ore of zinc, galena (PbS), an ore of lead, cinnabar (HgS), an ore of mercury, and molybdenite (MoS, an ore of molybdenum. Pyrite (FeS), is the most commonly occurring sulfide, and can be found in most geological environments. It is not, however, an ore of iron, but can be instead oxidized to produce sulfuric acid. Related to the sulfides are the rare sulfosalts, in which a metallic element is bonded to sulfur and a semimetal such as antimony, arsenic, or bismuth. Like the sulfides, sulfosalts are
The K-Metal from Krypton The K-Metal from Krypton "The K-Metal from Krypton" is an unpublished Superman story written by Jerry Siegel in 1940 and originally illustrated by the Joe Shuster Studio. The reason why National Comics (later to become DC Comics) never published the story is not known. This storyline features the precursor to Kryptonite called "K-Metal" and Lois learning that Clark Kent is Superman. Like all Superman stories of the 1940s, the adventure originally had no title. The earliest known occurrence of the name "The K-Metal from Krypton" for the tale was in Gerard Jones' 2004 book "Men of Tomorrow". The story remained