Home Experimental VNIR reflectance spectroscopy of gypsum dehydration: Investigating the gypsum to bassanite transition
Article
Licensed
Unlicensed Requires Authentication

Experimental VNIR reflectance spectroscopy of gypsum dehydration: Investigating the gypsum to bassanite transition

  • Tanya N. Harrison EMAIL logo
Published/Copyright: April 2, 2015
Become an author with De Gruyter Brill

Abstract

The spectral behavior of gypsum dehydration in the visible to near-infrared (350-2500 nm) wavelength range was investigated by partially dehydrating the four main habits of gypsum (alabaster, satin spar, selenite, and massive) to form bassanite. Powdered samples of gypsum dehydrated at 100-115 °C and hand samples dehydrated at 115-130 °C, coinciding with a peak in mass (water) loss in the samples. As gypsum dehydrates, its characteristic H2O absorption bands at 1443 and 1945 nm shift to shorter wavelengths. Band depths and widths of absorptions at ~1200, 1400-1600, 1750, 1945, 2100-2200, and ~2400 nm all decrease with increasing temperature. The samples also underwent visible changes upon dehydration, both at the macroscopic and microscopic level, becoming very friable with an increase in fine grains. No consistent relationship was observed between dehydration temperature and grain size or habit. The samples were monitored for up to 20 months after dehydration, during which time none rehydrated to form gypsum. While the transition from gypsum to bassanite is very abrupt, bassanite does not readily rehydrate to form gypsum again in ambient conditions, and therefore may not be as unstable as previously thought by terrestrial occurrences of bassanite being predominantly restricted to hyperarid climates.

Received: 2010-8-2
Accepted: 2011-12-14
Published Online: 2015-4-2
Published in Print: 2012-4-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Veatchite: Structural relationships of the three polytypes
  2. Falsterite, Ca2MgMn2+2 (Fe2+0.5Fe3+0.5)4Zn4(PO4)8(OH)4(H2O)14, a new secondary phosphate mineral from the Palermo No. 1 pegmatite, North Groton, New Hampshire
  3. Pavlovskyite Ca8(SiO4)2(Si3O10): A new mineral of altered silicate-carbonate xenoliths from the two Russian type localities, Birkhin massif, Baikal Lake area and Upper Chegem caldera, North Caucasus
  4. Zaccagnaite-3R, a new Zn-Al hydrotalcite polytype from El Soplao cave (Cantabria, Spain)
  5. Incorporation of Si into TiO2 phases at high pressure
  6. TOF-SIMS and electron microprobe investigations of zoned magmatic orthopyroxenes: First results of trace and minor element analysis with implications for diffusion modeling
  7. Titanium in muscovite, biotite, and hornblende: Modeling, thermometry, and rutile activities of metapelites and amphibolites
  8. Polysaccharide-catalyzed nucleation and growth of disordered dolomite: A potential precursor of sedimentary dolomite
  9. High-pressure and high-temperature phase transitions in FeTiO3 and a new dense FeTi3O7 structure
  10. Compressibility and thermal expansion of hydrous ringwoodite with 2.5(3) wt% H2O
  11. Vibrational and elastic properties of ferromagnesite across the electronic spin-pairing transition of iron
  12. Electronic spin states of ferric and ferrous iron in the lower-mantle silicate perovskite
  13. Experimental VNIR reflectance spectroscopy of gypsum dehydration: Investigating the gypsum to bassanite transition
  14. Nature of rehydroxylation in dioctahedral 2:1 layer clay minerals
  15. Thermal behavior of afghanite, an ABABACAC member of the cancrinite group
  16. Experimental incorporation of Th into xenotime at middle to lower crustal P-T utilizing alkali-bearing fluids
  17. Sol-gel synthesis of nanocrystalline fayalite (Fe2SiO4)
  18. The heat capacity of fayalite at high temperatures
  19. Structural trends for celestite (SrSO4), anglesite (PbSO4), and barite (BaSO4): Confirmation of expected variations within the SO4 groups
  20. The dehydroxylation of serpentine group minerals
  21. Formation of nanoscale Th-coffinite
  22. Magnetic and low-temperature structural behavior of clinopyroxene-type FeGeO3: A neutron diffraction, magnetic susceptibility, and 57Fe Mössbauer study
  23. Crystal structure and thermal expansion of aragonite-group carbonates by single-crystal X-ray diffraction
  24. The lower-pressure stability of glaucophane in the presence of paragonite and quartz in the system Na2O-MgO-Al2O3-SiO2-H2O
  25. Coralloite, Mn2+Mn23+(AsO4)2(OH)2·4H2O, a new mixed valence Mn hydrate arsenate: Crystal structure and relationships with bermanite and whitmoreite mineral groups
  26. The crystal structure of metanatroautunite, Na[(UO2)(PO4)](H2O)3, from the Lake Boga Granite, Victoria, Australia
  27. Petedunnite (CaZnSi2O6): Stability and phase relations in the system CaO-ZnO-SiO2
  28. Revision of the crystal structure and chemical formula of weeksite, K2(UO2)2(Si5O13)·4H2O
  29. Electron backscatter diffraction (EBSD) analyses of phyllosilicates in petrographic thin sections
Downloaded on 9.9.2025 from https://www.degruyterbrill.com/document/doi/10.2138/am.2012.3667/html
Scroll to top button