Plumosite is a questionable mineral. Most of the time, it can refer to any feather
ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...
, i.e. any ore that forms fine capillaries within the surrounding rock.
Older specimens could be either
boulangerite
Boulangerite or ''antimonbleiblende'' is an uncommon monoclinic orthorhombic sulfosalt mineral, lead antimony sulfide, formula Pb5Sb4S11. It was named in 1837 in honor of French mining engineer Charles Boulanger (1810–1849),http://www.mindat.o ...
,
jamesonite or
zinkenite (Pb
2Sb
2S
5, sulfosalt mineral).
Mineralienatlas
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References
Mineralogy
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