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 containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

, i.e. any ore that forms fine capillaries within the surrounding rock. Older specimens could be either

boulangerite Boulangerite 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.org/min-738.html Mindat a ...

jamesonite Jamesonite is a sulfosalt mineral, a lead, iron, antimony sulfide with formula Pb4FeSb6S14. With the addition of manganese it forms a series with benavidesite.http://rruff.geo.arizona.edu/doclib/hom/jamesonite.pdf Handbook of Mineralogy It is a ...

zinkenite Zinkenite is a steel-gray metallic sulfosalt mineral composed of lead antimony sulfide Pb9 Sb22 S42. Zinkenite occurs as acicular needle-like crystals. It was first described in 1826 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germa ...

(Pb₂Sb₂S₅, sulfosalt mineral).Mineralienatlas
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References

Mineralogy {{Mineral-stub