Definition of "pyrrhotite" []

• A brownish-bronze iron sulfide mineral, FeS, characterized by weak magnetic properties and used as an iron ore and in the manufacture of sulfuric acid. Also called magnetic pyrites. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "• A few minerals are magnetic such as pyrrhotite and magnetite."
• "Like PAHs, these minerals -- mainly iron compounds called magnetite and pyrrhotite -- can come from inorganic sources."
• "However, inorganic precipitation of magnetite and pyrrhotite require just the opposite conditions: high pH rather than low acidic pH conditions."