Schorl Mineral Data
General Schorl Information
Chemical Formula:
NaFe++3Al6(BO3)3Si6O18(OH)4
Composition:
Molecular Weight = 1,053.38 gm
Sodium 2.18 % Na 2.94 % Na2 O
Aluminum 15.37 % Al 29.04 % Al2 O3
Iron 15.91 % Fe 20.46 % FeO
Silicon 16.00 % Si 34.22 % SiO2
Boron 3.08 % B 9.91 % B2 O3
Hydrogen 0.38 % H 3.42 % H2 O
Oxygen 47.08 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
NaFe2+ 3 Al6 (BO3 )3 Si6 O18 (OH)4
Environment:
Granites, diorites, gabbro pegmatites, greisens, skarns and quartz veins.
IMA Status:
Valid Species (Pre-IMA) 1524 (Dana # Changed from 61.3.1.10)
Locality:
Sonnenberg, Bodenmais and Spessart, Germany. Link to MinDat.org Location Data.
Name Origin:
Old name of unknown origin.
Name Pronunciation:
Schorl
Synonym:
ICSD 74180
PDF 43-1464
Tourmaline
Schorl Image
Images:
Images:
Schorl
Comments: Parallel grouping of sharp, black schorl crystals showing terminations.
Location: Davib Ost, Erongo Mountains Namibia.
Scale: Crystal size: 1.7 x 1.4 cm.
© Fabre Minerals
Schorl Crystallography
Axial Ratios:
a:c = 1:0.44996
Cell Dimensions:
a = 15.99, c = 7.195, Z = 3; V = 1,593.16 Den(Calc)= 3.29
Crystal System:
Trigonal - Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m
X Ray Diffraction:
By Intensity(I/Io ): 2.576(1), 2.961(0.85), 3.99(0.85),
Forms:
Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize
Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu
Help on Above
Forms:
( 0 2 1 )
( 1 0 1 )
( 1 2 0)
( 1 0 0)
( 1 0 1)
( 0 2 1)
Warning: this java applet does not work in some browsers because of security restrictions.
Physical Properties of Schorl
Cleavage:
{1011} Indistinct
Color:
Black, Brownish black, Greenish black, Bluish black.
Density:
3.1 - 3.2, Average = 3.15
Diaphaneity:
Opaque
Fracture:
Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Habit:
Striated - Parallel lines on crystal surface or cleavage face.
Hardness:
7.5 - Garnet
Luminescence:
Piezoelectric.
Luster:
Vitreous (Glassy)
Streak:
brown
Optical Properties of Schorl
Dichroism (e):
light brown, buff, or light gray.
Dichroism (w):
dark brown, black, or deep gray.
Gladstone-Dale:
CI meas = 0.007 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = 0.05 (Good) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.1979,KPDmeas = 0.2067,KC = 0.2083 Ncalc = 1.65 - 1.69
Optical Data:
Uniaxial (-), e=1.633-1.64, w=1.66-1.672, bire=0.0270-0.0320.
Calculated Properties of Schorl
Electron Density:
Bulk Density (Electron Density)=3.10 gm/cc note: Specific Gravity of Schorl =3.15 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PESchorl = 5.85 barns/electronU=PESchorl x r Electron Density= 18.11 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Schorl is Not Radioactive
Schorl Classification
Dana Class:
61.03e.01.10 (61) Cyclosilicate Six-Membered Rings
(61.03e) with borate groups (Sodic Tourmaline Subgroup)
(61.03e.01) Schorl Subgroup
61.03e.01.09 Dravite ! NaMg3Al6(BO3)3Si6O18(OH)4 R 3m 3m
61.03e.01.10 Schorl ! NaFe3Al6(BO3)3Si6O18(OH)4 R 3m 3m
61.03e.01.10a Schorl-(F) ! NaFe3Al6Si6O18)(BO3)3(OH)3(F,OH) R 3m 3m
61.03e.01.11 Chromdravite ! NaMg3(Cr,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m
61.03e.01.12 Vanadiumdravite ! NaMg3V6(Si6O18)(BO3)3(OH)4 R 3m 3m
Strunz Class:
09.CK.05 09 - SILICATES (Germanates)
09.C - Cyclosilicates
09.CK -[Si6O18]12- 6-membered single rings, with insular complex anions
09.CK.05 Chromdravite ! NaMg3(Cr,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Feruvite ! (Ca,Na)(Fe,Mg,Ti)3(Al,Mg,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Dravite NaMg3Al6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Buergerite ! NaFe3Al6(BO3)3Si6O21F R 3m 3m
09.CK.05 Foitite ! []Na<0.5(Fe,Al)3Al6Si6O18(BO3)3(OH)4 R 3m 3m
09.CK.05 Liddicoatite ! Ca(Li,Al)3Al6(BO3)3Si6O18(O,OH,F)4 R 3m 3m
09.CK.05 Elbaite Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Rossmanite ! []LiAl2Al6(Si6O18)(BO3)3(OH)4 R 3m 3m
09.CK.05 Olenite ! NaAl3Al6(BO3)3(Si6O18)(O,OH)4 R 3m 3m
09.CK.05 Povondraite ! (Na,K)(Fe,Fe)3(Fe,Mg,Al)6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Schorl NaFe3Al6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Uvite (Ca,Na)(Mg,Fe)3Al5Mg(BO3)3Si6O18(OH,F)4 R 3m 3m
09.CK.05 Vanadiumdravite ! NaMg3V6(Si6O18)(BO3)3(OH)4 R 3m 3m
09.CK.05 Magnesiofoitite ! [](Mg2Al)Al6(Si6O18)(BO3)3(OH)4 R 3m 3m
09.CK.05 Hydroxyuvite ! CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) R 3m 3m
09.CK.05 Schorl-(F) ! NaFe3Al6Si6O18)(BO3)3(OH)3(F,OH) R 3m 3m
Other Schorl Information
References:
NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)
See Also:
Links to other databases for Schorl :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - CalTech Mineral Spectroscopy
7 - EUROmin Project
8 - Ecole des Mines de Paris
9 - Franklin Minerals(Dunn)
10 - GeoScienceWorld
11 - Google Images
12 - Google Scholar
13 - Handbook of Mineralogy (MinSocAm)
14 - Handbook of Mineralogy (UofA)
15 - MinDAT
16 - Mineral and Gemstone Kingdom
17 - Mineralienatlas (Deutsch)
18 - Online Mineral Museum
19 - QUT Mineral Atlas
20 - Ruff.Info
21 - Scandinavian mineral gallery
22 - WWW-MINCRYST
23 - YupRocks
Search for Schorl using:
[AOL ]
[Bing ]
[Dog Pile ]
[GeoScienceWorld ]
[HotBot ]
[Ixquick ]
[Lycos ]
[MAMMA ]
[Scirus ]
[Teoma ]
[WebCrawler ]
[Wikipedia ]
[YAHOO ]
Visit our Advertisers for Schorl :
Ask about Schorl here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Espa�ol
Print or Cut-and-Paste your Schorl Specimen Label here :
Schorl
NaFe++3Al6(BO3)3Si6O18(OH)4
Dana No: 61.03e.01.10 Strunz No: 09.CK.05
Locality:
Notes:
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.