Mineralogy Database

Johnwalkite Mineral Data

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General Johnwalkite Information

Help on Chemical Formula: Chemical Formula: K(Mn++,Fe+++,Fe++)2(Nb,Ta)(PO4)2O2((H2O),OH)2
Help on Composition: Composition: Molecular Weight = 480.93 gm
   Potassium    7.32 %  K     8.81 % K2O
   Magnesium    0.51 %  Mg    0.84 % MgO
   Tantalum     3.76 %  Ta    4.59 % Ta2O5
   Manganese   11.42 %  Mn   14.75 % MnO
   Niobium     15.45 %  Nb   22.11 % Nb2O5
   Iron         9.29 %  Fe   13.28 % Fe2O3
   Phosphorus  12.24 %  P    28.04 % P2O5
   Hydrogen     0.75 %  H     6.74 % H2O
   Oxygen      39.26 %  O
              ______        ______ 
              100.00 %       99.17 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: K0.9Mn2+Fe3+0.7Mg0.1Nb0.8Ta0.1Fe3+0.1O2(PO4)1.9(H2O)1.4(OH)0.8
Help on Environment: Environment: Secondary mineral derived from the dissolution of triphylite-lithiophilite and columbite-tantalite in a complex granite pegmatite.
Help on IMA Status: IMA Status: Approved IMA 1986
Help on Locality: Locality: Expectation pegmatite at the Champion mine, about 2.5 km southeast of Keystone, Pennington County, South Dakota, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Richard JOHNson (1936-1998) and Frank WALKup (1943-1993), mineral preparators, National Museum of Natural History, Washington, D. C., USA.
Help on Name Pronunciation: Name Pronunciation: Johnwalkite + Pronunciation Say JOHNWALKITE