Earlandite
{{Infobox mineral
| name = Earlandite
| category = Organic minerals
| image = Ca-citrate-tetrahydrate.png
| imagesize = 260px
| caption =
| formula = [Ca3(C6H5O7)2(H2O)2]·2H2O
| strunz = 10.AC.15
| system = Triclinic
| symmetry = P{{overline|1}} (No. 2)
| unit cell = a = 5.9466(4), b = 10.2247(8)
c = 16.6496(13) [Å]; Z = 2
| color = White, pale yellow
| habit = Nodular
| twinning =
| cleavage =
| fracture =
| mohs =
| luster =
| refractive = nα = 1.515
nβ = 1.530
nγ = 1.580
| opticalprop = Biaxial (+)
| 2V = 60°
| birefringence = δ = 0.065
| pleochroism =
| streak = White
| gravity = 1.80–1.95 (measured), 2.00 (calculated)
| melt =
| fusibility =
| diagnostic = Fine-grained and wart-like nodule crystal habit
| solubility = Insoluble
| diaphaneity = Transparent
| other =
{{cite journal
| first1= Eberhardt | last1= Herdtweck
| first2= Tobias | last2= Kornprobst
| first3 =Roland | last3=Sieber
| first4 = Leo | last4= Straver
| first5 = Johann | last5= Plank
| title= Crystal Structure, Synthesis, and Properties of tri-Calcium di-Citrate tetra-Hydrate [Ca3(C6H5O7)2(H2O)2]·2H2O
| journal= Z. Anorg. Allg. Chem.| year = 2011| volume= 637| issue= 6| pages= 655–659| doi= 10.1002/zaac.201100088
}}[http://www.mindat.org/min-1344.html Earlandite]. Mindat.org{{cite book|editor1=Anthony, John W. |editor2=Bideaux, Richard A. |editor3=Bladh, Kenneth W. |editor4=Nichols, Monte C. |title= Handbook of Mineralogy|publisher= Mineralogical Society of America|place= Chantilly, VA, US|url=http://rruff.info/doclib/hom/earlandite.pdf|chapter=Earlandite|isbn=0962209740 |volume=V (Borates, Carbonates, Sulfates)|year=2003}}
[http://webmineral.com/data/Earlandite.shtml Earlandite]. Webmineral
}}
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. Its crystal symmetry was first assigned as orthorhombic, then as monoclinic, and finally as triclinic.
References
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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.