pyrolusite
noun
py·ro·lu·site ˌpī-rō-ˈlü-ˌsīt 
: a soft black or steel-gray mineral of metallic luster consisting of manganese dioxide that is the most important ore of manganese
Word History
Etymology
German Pyrolusit, from Greek pyr- + lousis washing, from louein to wash — more at lye
First Known Use
1828, in the meaning defined above
- supersubtlety
- supersurgeons
- supersweet
- supersymmetric
- supersymmetries
- supersymmetry
- supersystem
- supersystems
- supertanker
- supertankers
- supertax
- supertaxes
- supertemporal
- superterranean
- superterraneous
- superterrene
- superterrestrial
- superterrific
- superthick
- superthin
- superthriller
- superthrillers
- supertight
- supertitle
- supertitles