Lansfordite

Lansfordite
General
CategoryCarbonates
Formula
(repeating unit)		MgCO3·5H2O
IMA symbolLfd[1]
Strunz classification5/D.01-30
Dana classification15.1.6.1
Crystal systemMonoclinic
Space groupP21/c (No. 14)
Unit cella=7.3458 Å, b=7.6232 Å, c=12.4737 Å, β=101.722°
Identification
Formula mass174.39
ColourColourless, white after exposure
Crystal habitCrystals, stalactites terminated by crystal faces, efflorescences, parallel growths.
CleavagePerfect, Distinct
Mohs scale hardness2.5
LusterVitreous (if fresh)
StreakWhite
DiaphaneityTranslucent, opaque after exposure
Specific gravity1.6
Density1.6
Birefringence0.042

Lansfordite is a mineral of magnesium carbonate (MgCO
3). It represents the pentahydrate of magnesium carbonate, and has the total formula MgCO3·5H2O .[2] Landsfordite was discovered in 1888 in a coal mine in Lansford, Pennsylvania. It crystallizes in the monoclinic system (space group P21/c[3]) and typically occurs as colorless to white prismatic crystals and stalactitic masses.[4] It is a soft mineral, Mohs hardness of 2.5, with a low specific gravity of 1.7. It is transparent to translucent with refractive indices of 1.46 to 1.51.[5] The mineral will effloresce at room temperature, producing nesquehonite.[6]

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. ^ "Lansfordite Mineral Data". www.webmineral.com. Retrieved 2021-02-15.
  3. ^ Liu, B.N.; Zhou, X.T.; Cui, X.S.; Tang, J.G. (1990). "Synthesis of lansfordite MgCO3*5H2O and its crystal structure investigation". Science in China. B33: 1350–1356.
  4. ^ "LANSFORDITE". euromin.w3sites.net. Retrieved 2021-02-15.
  5. ^ "Lansfordite". www.mindat.org. Retrieved 2021-02-15.
  6. ^ "Lansfordite" (PDF). Handbook of Mineralogy. Retrieved 15 February 2021.


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