Pumpellyite

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Pumpellyite
Mineraly.sk - pumpellyit.jpg
General
Category Sorosilicate
IMA symbol Pmp [1]
Strunz classification 9.BG.20
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group A2/m
Identification
ColorOlive green to bluish green
Cleavage Good in two directions
Fracture Uneven
Tenacity Brittle
Mohs scale hardness5.5-6
Luster Vitreous, dull
Streak White
Diaphaneity Translucent
Specific gravity 3.2
References [2] [3]

Pumpellyite is a group of closely related sorosilicate minerals:

Pumpellyite crystallizes in the monoclinic-prismatic crystal system. It typically occurs as blue-green to olive green fibrous to lamellar masses. It is translucent and glassy with a Mohs hardness of 5.5 and a specific gravity of 3.2. It has refractive indices of nα=1.674–1.748, nβ=1.675–1.754 and nγ=1.688–1.764.

Pumpellyite occurs as amygdaloidal and fracture fillings in basaltic and gabbroic rocks in metamorphic terranes. It is an indicator mineral of the prehnite-pumpellyite metamorphic facies. It is associated with chlorite, epidote, quartz, calcite and prehnite.

It was first described in 1925 for occurrences in the Calumet mine, Houghton Co., Keweenaw Peninisula, Michigan, and named for United States geologist Raphael Pumpelly (1837–1923). [9]

See also

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. Mineralienatlas
  3. Chesterman, Charles W. (1978). The Audubon Society field guide to North American rocks and minerals. New York: Alfred A. Knopf. p. 567. ISBN   0394502698.
  4. Mindat - Pumpellyite-(Mg)
  5. Mindat - Pumpellyite-(Fe2+)
  6. Mindat - Pumpellyite-(Fe3+)
  7. Mindat - Pumpellyite-(Mn2+)
  8. Mindat - Pumpellyite (Al)
  9. Huber, N. King (1975). The Geologic Story of Isle Royale National Park, USGS Bulletin 1309. Washington: U.S. Government Printing Office. p. 58.