Griffithite Mineral Data (original) (raw)
General Griffithite Information
4(Mg,Fe,Ca)O.(Al,Fe)2O3.5SiO2•7(H2O)
Molecular Weight = 764.30 gm
Calcium 2.10 % Ca 2.93 % CaO
Magnesium 7.63 % Mg 12.66 % MgO
Aluminum 5.30 % Al 10.01 % Al2O3
Iron 12.42 % Fe 11.28 % FeO / 5.22 % Fe2O3
Silicon 18.37 % Si 39.31 % SiO2
Hydrogen 1.85 % H 16.50 % H2O
Oxygen 52.33 % O
______ ______
100.00 % 97.91 % = TOTAL OXIDE
Mg2.4Fe2+1.2Ca0.4Al1.5Fe3+0.5Si5O18�7(H2O)
Amygdaloidal cavities in basalt. A variety of ferroan saponite.
Not Approved IMA
Cahuenga Pass, Griffith Park, Los Angeles, California, USA. Link to MinDat.org Location Data.
Named after its locality.
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Griffithite Crystallography
Physical Properties of Griffithite
{001} Perfect
Dark green.
2.31
Subtransparent to subtranslucent
Platy - Sheet forms (e.g. micas).
1 - Talc
Non-fluorescent.
Vitreous - Dull
Magnetic after heating
green
Optical Properties of Griffithite
CI meas= -0.028 (Excellent) - where the CI = (1-KPDmeas/KC)
KPDmeas= 0.2341,KC= 0.2277
Ncalc = 1.53
Biaxial (-), a=1.485, b=1.565, g=1.572, bire=0.0870
pale yellow.
olive green.
brownish green.
Calculated Properties of Griffithite
Bulk Density (Electron Density)=2.32 gm/cc
note: Specific Gravity of Griffithite =2.31 gm/cc.
Fermion Index = 0.01
Boson Index = 0.99
PEGriffithite = 4.93 barns/electron
U=PEGriffithite x rElectron Density= 11.46 barns/cc.
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Griffithite is Not Radioactive
Griffithite Classification
71.00.00.00 (71)Phyllosilicate Minerals
(71.00)Without Dana Classification Numbers
(71.00.00)Chlorite Group
71.00.00.00 Bariumbannisterite* (K,H3O)(Ba,Ca)(Mn,Fe,Mg)21(Si,Al)32O80(O,OH)16•4-12(H2O) Mono
71.00.00.00 Ekmanite? (Fe,Mg,Mn,Fe)3(Si,Al)4O10(OH)2•2(H2O) Unk Ortho
71.00.00.00 Griffithite* 4(Mg,Fe,Ca)O.(Al,Fe)2O3.5SiO2•7(H2O) Mono
71.00.00.00 Orlovite KLi2TiSi4O11F C 2 2
71.00.00.00 Shlykovite KCa[Si4O9(OH)]•3H2O P 21/c 2/m
71.00.00.00 Spodiophyllite? (Na,K)4(Mg,Fe)3(Fe,Al)2(Si8O24) Mono
71.00.00.00 Voloshinite Rb(LiAl1.5[]0.5)(Al0.5Si3.5)O10F2 C 2/c 2/m
09.EC.45 09 - SILICATES (Germanates)
09.E - Phyllosilicates
09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
09.EC.45 Griffithite* 4(Mg,Fe,Ca)O.(Al,Fe)2O3.5SiO2•7(H2O) Mono
09.EC.45 Hectorite Na0,3(Mg,Li)3Si4O10(OH)2 C 2/m 2/m
09.EC.45 Swinefordite (Li,Ca0.5,Na)0.72(Li,Al,Mg)2.66(Si,Al)4O10(OH,F)2•2(H2O) C 2/m (MON or ORTH) 2/m
09.EC.45 Zincsilite Zn3Si4O10(OH)2•4(H2O)(?) C 2/m ? 2/m
09.EC.45 Saponite (Ca/2,Na)0,3(Mg,Fe)3(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m
09.EC.45 Sauconite Na0,3Zn3(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m
09.EC.45 Spadaite MgSiO2(OH)2•(H2O)(?) Ortho
09.EC.45 Sobotkite? (K,Ca0.5)0.33(Mg,Al)3(Si3Al)O10(OH)2•1-5(H2O) Unk. Mono
09.EC.45 Stevensite (Ca0.5,Na)0.33(Mg,Fe)3Si4O10(OH)2•n(H2O) Unk (ORTH ?) Mono
09.EC.45 Ferrosaponite! Ca0.3(Fe,Mg,Fe)3(Si,Al)4O10(OH)2•4(H2O) C? Mono
Other Griffithite Information
NAME( Ford32) PHYS. PROP.(Dana) OPTIC PROP.(Ford32)
Links to other databases for Griffithite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info
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Print or Cut-and-Paste your Griffithite Specimen Label here :
Griffithite
4(Mg,Fe,Ca)O.(Al,Fe)2O3.5SiO2•7(H2O)
Dana No: 71.00.00.00 Strunz No: 09.EC.45
Locality:
Notes: