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Schorl

Big Photo

Olgiasca-Malpensata (Piona), Colico, Lecco Province, Lombardy, Italy
© Sarah Sudcowsky

Show Schorl Photos (385)
Formula:
[Na][Fe
2+
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
System:TrigonalColour:Bluish-black to black, ...
Lustre:Vitreous, ResinousHardness:7
Name:The early history of the mineral schorl shows that the name "Schorl" was in use prior to the year 1400 (AD) because a village known today as Zschorlau (in Saxony, Germany) was then named "Schorl" (or minor variants of this name). This village had a nearby tin mine where, in addition to cassiterite, a lot of black tourmaline was found. The first relatively detailed description of schorl with the name "schürl" and its occurrence (various tin mines in the Saxony Ore Mountains) was written by Johannes Mathesius (1504-1565) in 1562 under the title "Sarepta oder Bergpostill". Up to about 1600, additional names used in the German language were "Schurel", "Schörle", and "Schurl". From the 18th century on, the name "Schörl" was mainly used in the German-speaking area. In English, the names "shorl" and "shirl" were used in the 18th century for schorl. In the 19th century the names "common schorl", "schörl", "schorl" and "iron tourmaline" were used in the Anglo-Saxon area (Ertl, 2006).


Tourmaline Group. Elbaite-Schorl Series.

See also Unnamed (F-analogue of Schorl).

Classification of Schorl

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered" 1524
Strunz 8th edition ID:8/E.19-50
Nickel-Strunz 10th (pending) edition ID:9.CK.05

9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si6O18]12- 6-membered single rings, with insular complex anions
Dana 7th edition ID:61.3.1.12
Dana 8th edition ID:61.3.1.10

61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
Hey's CIM Ref.:17.5.44

17 : Silicates Containing other Anions
5 : Borosilicates
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Occurrences of Schorl

Geological Setting:In granites and granitic pegmatites, high temperature hydrothermal veins, metamorphic rocks.

Physical Properties of Schorl

Lustre:Vitreous, Resinous
Diaphaneity (Transparency):Translucent, Opaque
Colour:Bluish-black to black, sometimes brownish-black, rarely greenish-black.
Streak:Greyish-white to bluish-white.
Hardness (Mohs):7
Tenacity:Brittle
Cleavage:Poor/Indistinct
Very poor on {1120}, {1011}
Fracture:Irregular/Uneven, Sub-Conchoidal
Density (measured):3.18 - 3.22 g/cm3
Density (calculated):3.244 g/cm3

Crystallography of Schorl

Crystal System:Trigonal
Class (H-M):3m - Ditrigonal Pyramidal
Space Group:R3m
Cell Parameters:a = 15.98(5) Å, c = 7.15(3) Å
Ratio:a:c = 1 : 0.447
Unit Cell Volume:V 1,581.21 ų (Calculated from Unit Cell)
Z:3
Morphology:Prismatic to acicular
Twinning:Rarely on {1010} and {4041}

Optical Data of Schorl

Type:Uniaxial (-)
RI values: nω = 1.660 - 1.672 nε = 1.635 - 1.650
Maximum Birefringence:δ = 0.025

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Pleochroism:Strong
Comments:O= yellow brown
E= pale yellow, pale brown
Comments:Under strain, may be slightly biaxial

Chemical Properties of Schorl

Formula:
[Na][Fe
2+
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
Essential elements:Al, B, Fe, H, Na, O, Si
All elements listed in formula:Al, B, Fe, H, Na, O, Si
Common Impurities:Mn,Mg,Ca,Li,Cr,Ti,F,K

Relationship of Schorl to other Species

Series:Forms a series with Dravite (see here)
Forms a series with Elbaite (see here)
Member of:Tourmaline Group
Related Minerals - Nickel-Strunz Grouping):
9.CK.05Buergerite
[Na][Fe
3+
3
][Al
 
6
][O
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Chromdravite
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Dravite
[Na][Mg
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Elbaite
[Na][(Li,Al)
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Feruvite
[Ca][(Fe
2+
 
 ,Mg)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Foitite
[ ][Fe
2+
2
(Al,Fe
3+
 
)][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Liddicoatite
[Ca][Li
 
2
Al][Al
 
6
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Olenite
([ ],Na)[(Al,Li)
 
3
][Al
 
6
][(O,OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Povondraite
[Na][Fe
3+
3
][Fe
3+
6
][O
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Uvite
[Ca][(Mg,Fe
2+
 
)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Magnesiofoitite
[ ][Mg
 
2
(Al,Fe
3+
 
 )][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Rossmanite
[ ][LiAl
 
2
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Vanadiumdravite
[Na][Mg
 
3
][V
3+
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Oxy-Dravite
Na (MgAl
 
2
)(MgAl
 
5
)Si
 
6
O
 
18
(BO
 
3
)
 
3
(OH)
 
3
O
9.CK.05Oxy-rossmanite
[ ][LiAl
 
2
]Al
 
6
(BO
 
3
)
 
3
[Si
 
6
O
 
18
](OH)
 
3
(O)
9.CK.10Abenakiite-(Ce)
Na
 
26
Ce
 
6
[O|SO
 
2
|(CO
 
3
)
 
6
|(PO
 
4
)
 
6
|Si
 
6
O
 
18
]
9.CK.15Scawtite
Ca
 
7
Si
 
6
(CO
 
3
)O
 
18
·2H
 
2
O
9.CK.20Steenstrupine-(Ce)
Na
 
14
Mn
2+
2
(Fe
3+
 
,Mn
3+
 
)
 
2
Ce
 
6
(Zr,Th)[(OH)
 
2
|HPO
 
4
|(PO
 
4
)
 
6
|(Si
 
6
O
 
18
)
 
2
]·2H
 
2
O
9.CK.20Thorosteenstrupine
CaMnThSi
 
4
O
 
11
(OH)F·6H
 
2
O
Related Minerals - Hey's Index Grouping:
17.5.1Manandonite
LiAl
 
4
Si
 
3
BO
 
10
(OH)
 
6
17.5.2Reedmergnerite
Na[BSi
 
3
O
 
8
]
17.5.3Searlesite
NaBSi
 
2
O
 
5
(OH)
 
2
17.5.4Olenite
([ ],Na)[(Al,Li)
 
3
][Al
 
6
][(O,OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.5Elbaite
[Na][(Li,Al)
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.6Kalborsite
K
 
6
[Cl|B(OH)
 
4
|Al
 
4
Si
 
6
O
 
20
]
17.5.7Boromuscovite
KAl
 
2
[(OH)
 
2
|BSi
 
3
O
 
10
]
17.5.8Poudretteite
KNa
 
2
B
 
3
Si
 
12
O
 
30
17.5.9Liddicoatite
[Ca][Li
 
2
Al][Al
 
6
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.10Datolite
CaB[OH|SiO
 
4
]
17.5.11Danburite
Ca[BSiO
 
4
]
 
2
17.5.12Howlite
Ca
 
2
B
 
5
SiO
 
9
(OH)
 
5
17.5.13Bakerite
Ca
 
4
B
 
4
[(OH)
 
4
|HBO
 
4
|(SiO
 
4
)
 
3
]
17.5.14Oyelite
Ca
 
10
Si
 
8
B
 
2
O
 
29
·12.5H
 
2
O
17.5.15Kornerupine
Mg
 
3
Al
 
6
(Si,Al,B)
 
5
O
 
21
(OH)
17.5.16Harkerite
Ca
 
24
Mg
 
8
Al
 
2
Si
 
8
(O,OH)
 
32
(BO
 
3
)
 
8
(CO
 
3
)
 
8
(H
 
2
O,Cl)
17.5.17Serendibite
(Ca,Na)
 
2
(Mg,Fe
2+
 
)
 
3
(Al,Fe
3+
 
)
 
3
[O
 
2
|(Si,Al,B)
 
6
O
 
18
]
17.5.18Stillwellite-(Ce)
(Ce,La,Ca)BSiO
 
5
17.5.19Tadzhikite-(Ce)
(Ca,Ce)
 
4
(Ca,Y)
 
2
(Ti
4+
 
,Fe
3+
 
,Al)[B
 
4
Si
 
4
O
 
22
(O,OH)
 
6
](OH)
 
2
17.5.20Melanocerite-(Ce)
(Ce,Ca)
 
5
(Si,B)
 
3
O
 
12
(OH,F)·nH
 
2
O
17.5.21Okanoganite-(Y)
(Na,Ca)
 
3
(Y,Ce)
 
12
Si
 
6
B
 
2
O
 
27
F
 
14
17.5.22Tritomite-(Ce)
(Ce,La,Y,Th)
 
5
(Si,B)
 
3
(O,OH,F)
 
13
17.5.23Tritomite-(Y)
(Y,Ca,La,Fe)
 
5
(Si,B,Al)
 
3
(O,OH,F)
 
13
17.5.24Cappelenite-(Y)
Ba(Y,Ce)
 
6
Si
 
3
B
 
6
O
 
24
F
 
2
17.5.25Dumortierite
(Al,Fe
3+
 
)
 
7
[O
 
3
|BO
 
3
|(SiO
 
4
)
 
3
]
17.5.26Holtite
(Ta,Sb)Al
 
6
[O
 
3
|BO
 
3
|(SiO
 
4
)
 
3
]
17.5.27Dravite
[Na][Mg
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.28 Ferridravite
17.5.29Axinite-(Mg)
Ca
 
2
MgAl
 
2
[OH|BSi
 
4
O
 
15
]
17.5.30Uvite
[Ca][(Mg,Fe
2+
 
)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.31Garrelsite
Ba
 
3
NaSi
 
2
B
 
7
O
 
16
(OH)
 
4
17.5.32Tienshanite
Na
 
2
BaMnTiB
 
2
Si
 
6
O
 
20
17.5.33Leucosphenite
BaNa
 
4
Ti
 
2
B
 
2
Si
 
10
O
 
30
17.5.34Taramellite
Ba
 
4
(Fe
3+
 
,Ti,Fe
2+
 
,Mg)
 
4
(B
 
2
Si
 
8
O
 
27
)O
 
2
Cl
 
x
17.5.35Titantaramellite
Ba
 
4
(Ti,Fe
3+
 
,Fe
2+
 
,Mg)
 
4
(B
 
2
Si
 
8
O
 
27
)O
 
2
Cl
 
x
17.5.36Nagashimalite
Ba
 
4
(V,Ti)
 
4
B
 
2
Si
 
8
O
 
27
(O,OH)
 
2
Cl
17.5.37Chromdravite
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.38Wawayandaite
Ca
 
6
Mn
 
2
BBe
 
9
Si
 
6
O
 
23
(OH,Cl)
 
15
17.5.39Werdingite
(Mg,Fe)
 
2
Al
 
14
Si
 
4
B
 
4
O
 
37
17.5.40Axinite-(Mn)
Ca
 
2
Mn
2+
 
Al
 
2
[OH|BSi
 
4
O
 
15
]
17.5.41Axinite
(Ca,Fe,Mn)Al
 
2
BSi
 
4
O
 
15
OH
17.5.42Tinzenite
(Ca,Mn
2+
 
,Fe
2+
 
)
 
3
Al
 
2
[OH|BSi
 
4
O
 
15
]
17.5.45Buergerite
[Na][Fe
3+
3
][Al
 
6
][O
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.46Feruvite
[Ca][(Fe
2+
 
 ,Mg)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.47Axinite-(Fe)
Ca
 
2
Fe
2+
 
Al
 
2
[OH|BSi
 
4
O
 
15
]
17.5.48Homilite
Ca
 
2
(Fe
2+
 
,Mg)B
 
2
[O|SiO
 
4
]
 
2
17.5.49Grandidierite
(Mg,Fe
2+
 
)(Al,Fe
3+
 
)
 
3
[O
 
2
|BO
 
3
|SiO
 
4
]
17.5.50Hyalotekite
(Ba,Pb,Ca,K)
 
6
(B,Si,Al)
 
2
(Si,Be)
 
10
O
 
28
(F,Cl)
17.5.51Hellandite-(Y)
(Ca,Y)
 
6
(Al,Fe
3+
 
)Si
 
4
B
 
4
O
 
20
(OH)
 
4
Related Minerals - Dana Grouping):
61.3.1.1Foitite
[ ][Fe
2+
2
(Al,Fe
3+
 
)][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.2Magnesiofoitite
[ ][Mg
 
2
(Al,Fe
3+
 
 )][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.3Rossmanite
[ ][LiAl
 
2
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.4Liddicoatite
[Ca][Li
 
2
Al][Al
 
6
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.5Uvite
[Ca][(Mg,Fe
2+
 
)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.6Feruvite
[Ca][(Fe
2+
 
 ,Mg)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.7Buergerite
[Na][Fe
3+
3
][Al
 
6
][O
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.8Povondraite
[Na][Fe
3+
3
][Fe
3+
6
][O
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.9Olenite
([ ],Na)[(Al,Li)
 
3
][Al
 
6
][(O,OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.10Elbaite
[Na][(Li,Al)
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.11Dravite
[Na][Mg
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.13Chromdravite
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.14Vanadiumdravite
[Na][Mg
 
3
][V
3+
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]

Other Names for Schorl

Synonyms:
AfrisiteSchirlSchorlite (of Hunt)Shorl
German names:
Schörl
Russian names:
Шерл
Spanish names:
Afrisita
Varieties:
Magnesian Schorl

Other Information

Electrical:Pyroelectric and piezoelectric.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Schorl

Reference List:Barsanov, G.P. and Yakovleva, M.E. (1965) Tourmalines of schorl composition. Akademiya Nauk SSSR, Mineralogicheshkii Muzei, Moscow: 16: 3-44.

Neiva, A.M.R. (1974) Geochemistry of tourmaline (schorlite) from granites, aplites and pegmatites from northern Portugal. Geochimica et Cosmochimica Acta: 38: 1307-1317.

Fortier, S. & Donnay, G. (1975): Schorl refinement showing composition dependence of the tourmaline structure. Canadian Mineralogist: 13: 173-177.

Povondra, P. (1981) The crystal chemistry of tourmalines of the schorl-dravite series. Acta Univ. Carol., Geol. 3: 223-264.

Leavens, P.B., Rheingold, A.L., and Dietrich, R.V. (1988) Crystal structure of a uvite-schorl tourmaline. V.M. Goldschmidt conference; program and abstracts: 56.

Foit, F.F., Jr. (1989), Crystal chemistry of alkali-deficient schorl and tourmaline structural relationships: American Mineralogist: 74: 422-431.

Aurisicchio, C., Ottolini, L., and Pezzotta, F. (1999) Electron- and on-microprobe analyses, and genetic interferences of tourmalines of the foitite-schorl solid solution, Elba Island (Italy). Eurpean Journal of Mineralogy: 11: 217-225.

Bloodaxe, E.S., J.M. Hughes, M.D. Dyar, E.S. Grew, and C.V. Guidotti (1999), Linking structure and chemistry in the schorl-dravite series: American Mineralogist: 84: 922-928.

Ertl, A., Pertlik, F., and Bernhardt, H.-J. (2001b) Ein hell-blauer Olenit-Schörl-Dravit Mischkristall von Ebersdorf, Niederösterreich: Strukturanalyse und Chemie. Mitt. Österr. Mineral. Ges.: 146: 75-77.

Grew, E.S., and Anovitz, L.M. (1996) BORON: Mineralogy, Petrology and Geochemistry, second edition, as revised (2002).

Ondrus, P., Vrana, S. & Maslan, M. (2002): Chemical composition and crystal structure refinement of schorl from the Lundazi pegmatite field, Zambia. Vestnik Ceskeho Geologickeho Ustavu 77, 23-28.

Bosi, F. & Lucchesi, S. (2004): Crystal chemistry of the schorl-dravite series. European Journal of Mineralogy 16, 335-344.

Ertl, A. (2006), Über die Etymologie und die Typlokalitäten des Minerals Schörl (About the etymology and the type-localities of schorl). (German with English abstract). Mitteilungen der Österreichischen Mineralogischen Gesellschaft, 152, 2006, pp 7–16. Min Abs. [06M/3855].

http://tw.strahlen.org/typloc/schoerl.html

Internet Links for Schorl

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