General Sinkankasite Information
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Help on Locality: Locality:
Barker pegmatite, SW of Keystone, Penninton County, South Dakota, USA. Link to 
MinDat.org Location Data.
Help on Name Origin: Name Origin:
Named for John Sinkankas (1915-2002), Captain, U.S. Navy, and author of books on minerals and gems.
PDF 42-597
Sinkankasite Image
Sinkankasite
Comments: White crystalline spray of acicular sinkankasite to 1mm on matrix.
Location: Barker mine, Keystone, Pennington County, South Dakota, USA.
Scale: Picture size 5 mm.
© Tom Loomis / Dakota Matrix
Sinkankasite Crystallography
Help on Cell Dimensions: Cell Dimensions:
a = 9.58, b = 9.79, c = 6.88, Z = 2; alpha = 108.1°, beta = 99.6°, gamma = 98.7° V = 597.79 Den(Calc)= 2.22
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Crystal Structure:
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Help on Above
Burns P C , Hawthorne F C , American Mineralogist , 80 (1995) p.620-627, The crystal structure of sinkankasite, a complex heteropolyhedral sheet mineral
Physical Properties of Sinkankasite
Help on Fracture: Fracture:
Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit:
Pseudomorphous - Occurs in the form of another mineral.
Optical Properties of Sinkankasite
Help on Gladstone-Dale: Gladstone-Dale:
CI meas= 0.038 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.025 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2357,KPDmeas= 0.2326,KC= 0.2417
Ncalc = 1.54 - 1.55
Help on Optical Data: Optical Data:
Biaxial (-), a=1.511, b=1.529, g=1.544, bire=0.0330, 2V(Calc)=82, 2V(Meas)=84. Dispersion r < v.
Calculated Properties of Sinkankasite
Help on Electron Density: Electron Density:
Bulk Density (Electron Density)=2.28 gm/ccnote: Specific Gravity of Sinkankasite =2.24 gm/cc.
Help on Photoelectric: Photoelectric:
PESinkankasite = 4.38 barns/electron
U=PESinkankasite x rElectron Density= 9.98 barns/cc.
Help on Radioactivity: Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Sinkankasite is
Not Radioactive
Sinkankasite Classification
(42.07)where (AB)5 (XO4)3 Zq キ x(H2O)
42.07.01.02 Eosphorite MnAl(PO4)(OH)2•(H2O) Bbam 2/m 2/m 2/m
42.07.01.03 Ernstite (Mn1-xFex)Al(PO4)(OH)2-xOx C 2/c or Cc Mono
08.DB -With only medium-sized cations, (OH, etc.):RO4 < 1:1
Other Sinkankasite Information