from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun Gypsum in the form of colorless clear crystals.

from The Century Dictionary.

  • noun [capitalized] A supposed inhabitant of the moon.
  • noun A foliated or crystallized and transparent variety of gypsum, often obtained in large thin plates somewhat resembling mica; also, specifically, a thin plate of this mineral used with the polarizing apparatus of the microscope.
  • noun In chem., a salt of selenium.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Chem.) A salt of selenious acid.
  • noun (Min.) A variety of gypsum, occuring in transparent crystals or crystalline masses.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun mineralogy A soft, glassy form of gypsum (chemical formula CaSO4·2H2O).
  • noun inorganic chemistry The anion SeO32− derived from selenous acid; any salt or ester of selenous acid.


from The American Heritage® Dictionary of the English Language, 4th Edition

[Latin selēnītēs, from Greek selēnītēs (lithos), moon (stone), selenite (so called because it was believed to wax and wane with the moon), from selēnē, moon; see selenium.]


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  • Selenite, satin spar, desert rose, and gypsum flower are the four crystalline varieties of gypsum.


    February 14, 2008