Microcline

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Microcline pendant
MFA Acc. #: 20.268

Description

A variety of potash Feldspar that is chemically identical to Orthoclase. However microcline has a triclinic crystalline system while orthoclase has a monoclinic crystalline system. Under a polarizing microscope, microcline displays a minute multiple twinning that forms a grating-like pattern. Amazon stone, or Amazonite, is a green microcline that has been used since antiquity for decorative items. Microcline is used in making glass, porcelain, and enamel. Major deposits are found in Italy (Baveno), Norway (Kragerø), Madagascar, Russia (the Urals), and the U.S. (Colorado).

Microcline (potassium feldspar)

Synonyms and Related Terms

amazonite; feldspar; microclina (Esp., Port.); microklien (Ned.)

FTIR (PMA)

Microcline, PMA.TIF

Raman

MicroclineRS.jpg


Physical and Chemical Properties

Color= colorless Crystal system = triclinic, may exhibit albite twinning Cleavage is perfect in one direction and good in another

Composition K2O-Al2O3-6SiO2
Microcline (green)

Resources and Citations

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 316
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • Ancient Egyptian Materials and Technologies, Paul Nicholson, Ian Shaw (eds.), Cambridge University Press, Cambridge, 2000 Comment: B.Aston, J.Harrell, I.Shaw, "Stone" p. 21-22.
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976