Earlandite

Earlandite
General
CategoryOrganic minerals
Formula
(repeating unit)		[Ca3(C6H5O7)2(H2O)2]·2H2O
IMA symbolEar[1]
Strunz classification10.AC.15
Crystal systemTriclinic
Space groupP1 (No. 2)
Unit cella = 5.9466(4), b = 10.2247(8)
c = 16.6496(13) [Å]; Z = 2
Identification
ColorWhite, pale yellow
Crystal habitNodular
StreakWhite
DiaphaneityTransparent
Specific gravity1.80–1.95 (measured), 2.00 (calculated)
Optical propertiesBiaxial (+)
Refractive indexnα = 1.515
nβ = 1.530
nγ = 1.580
Birefringenceδ = 0.065
2V angle60°
Diagnostic featuresFine-grained and wart-like nodule crystal habit
SolubilityInsoluble
References[2][3][4][5]

Earlandite, [Ca3(C6H5O7)2(H2O)2]·2H2O, is the mineral form of calcium citrate tetrahydrate. It was first reported in 1936 and named after the English microscopist and oceanographer Arthur Earland FRSE. Earlandite occurs as warty fine-grained nodules ca. 1 mm in size in bottom sediments of the Weddell Sea, off Antarctica.[4] Its crystal symmetry was first assigned as orthorhombic, then as monoclinic, and finally as triclinic.[2]

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. ^ a b Herdtweck, Eberhardt; Kornprobst, Tobias; Sieber, Roland; Straver, Leo; Plank, Johann (2011). "Crystal Structure, Synthesis, and Properties of tri-Calcium di-Citrate tetra-Hydrate [Ca3(C6H5O7)2(H2O)2]·2H2O". Z. Anorg. Allg. Chem. 637 (6): 655–659. doi:10.1002/zaac.201100088.
  3. ^ Earlandite. Mindat.org
  4. ^ a b Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (2003). "Earlandite". Handbook of Mineralogy (PDF). Vol. V (Borates, Carbonates, Sulfates). Chantilly, VA, US: Mineralogical Society of America. ISBN 0962209740.
  5. ^ Earlandite. Webmineral

Bibliography

  • Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 1105-1106.