adj. of, relating to, or consisting of pyrite or pyrites
the GNU version of the Collaborative International Dictionary of English
adj. Of or pertaining to pyrites; consisting of, or resembling, pyrites.
The Century Dictionary and Cyclopedia
Pertaining to pyrites; consisting of or resembling pyrites.
Word Usage
"Commercial coal cleaning (or beneficiation) facilities, particularly in the United States use physical cleaning techniques to reduce mineral matter and pyritic sulfur content."