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Eucryptite

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Big Photo

Foote Lithium Co. Mine (Foote Mine), Kings Mountain District, Cleveland Co., North Carolina, USA
© JBS 2006

Show Eucryptite Photos (39)



Formula:
LiAlSiO
 
4
System:TrigonalColour:Colorless, white, pale ...
Hardness:6½
Name:Named in 1880 by Brush and Dana from the Greek for "well concealed", in allusion to its occurrence embedded in albite. Also known as α-eucryptite or alpha-eucryptite.


Phenakite Group.

Classification of Eucryptite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/A.01-30
Nickel-Strunz 10th (pending) edition ID:9.AA.05

9 : SILICATES (Germanates)
A : Nesosilicates
A : Nesosilicates without additional anions; cations in tetrahedral [4] coordination
Dana 7th edition ID:51.1.1.3
Dana 8th edition ID:51.1.1.3

51 : NESOSILICATES Insular SiO4 Groups Only
1 : Insular SiO4 Groups Only with cations in [4] coordination
Hey's CIM Ref.:16.1.3

16 : Silicates Containing Aluminum and other Metals
1 : Aluminosilicates of Li
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Type Occurrence of Eucryptite

Type Locality:Fillow Quarry (Branchville Quarry; Branchville Mica Mine; Smith Mine), Branchville, Town of Ridgefield, Fairfield Co., Connecticut, USA
Year of Discovery:1880

Occurrences of Eucryptite

Geological Setting:In lithium-rich pegmatites, often as graphic intergrowths with albite derived from alteration of spodumene.

Physical Properties of Eucryptite

Lustre:Sub-Vitreous, Resinous, Greasy
Diaphaneity (Transparency):Transparent, Translucent
Comment:Usually sub-vitrous
Colour:Colorless, white, pale tan, pale gray.
Streak:White
Hardness (Mohs):6½
Tenacity:Brittle
Cleavage:Poor/Indistinct
Poor on {101¯0} and {0001}.
Fracture:Irregular/Uneven, Conchoidal
Comment:Pure masses from Bikita show conchoidal fracture.
Density (measured):2.657 - 2.666 g/cm3
Density (calculated):2.654 g/cm3

Crystallography of Eucryptite

Crystal System:Trigonal
Class (H-M):3 - Rhombohedral
Space Group:R3
Space Group Setting:R3
Cell Parameters:a = 13.48Å, c = 9.01Å
Ratio:a:c = 1 : 0.668
Unit Cell Volume:V 1,417.87 ų (Calculated from Unit Cell)
Z:18
Morphology:Usually massive, rarely in equant euhedral crystals with {101¯0}, {0001}, and {112¯0}. (Bikita: Hurlbut, 1962). More complec crystals found at Kings Mountain, North Carolina, USA.
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.
X-Ray Powder Diffraction:
d-spacingIntensity
6.74 (60)
4.20 (30)
3.96 (100)
3.89 (40)
3.37 (90)
2.74 (80)
2.55 (60)
2.38 (30)

Optical Data of Eucryptite

Type:Uniaxial (+)
RI values: nω = 1.570 - 1.573 nε = 1.583 - 1.587
Maximum Birefringence:δ = 0.013

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Low

Chemical Properties of Eucryptite

Formula:
LiAlSiO
 
4
Essential elements:Al, Li, O, Si
All elements listed in formula:Al, Li, O, Si
Analytical Data:Bikita Zimbabwe and Kings Mountain, NC
Gelatinizes in acids
SiO2 (49.32), (47.97)
Al2O3 (40.43), 40.28)
Li2O (9.72), (11.45)
Na2O (0.24). (0.26)
K2O (0.01), 0
Common Impurities:Na,K

Relationship of Eucryptite to other Species

Structurally related to group(s):
Phenakite Group
Common Associates:
SpodumeneQuartzPetaliteCleavelanditeLepidolite
Albite
Related Minerals - Nickel-Strunz Grouping):

- +
9.AA.05Phenakite
Be
 
2
SiO
 
4
9.AA.05Willemite
Zn
 
2
SiO
 
4
9.AA.10Liberite
Li
 
2
BeSiO
 
4
Related Minerals - Hey's Index Grouping:

- +
16.1.1Petalite
LiAl(Si
 
4
O
 
10
)
16.1.2Spodumene
LiAlSi
 
2
O
 
6
16.1.4Virgilite
LiAlSi
 
2
O
 
6
16.1.5Cookeite
LiAl
 
4
(AlSi
 
3
O
 
10
)(OH)
 
8
16.1.6Bikitaite
LiAlSi
 
2
O
 
6
 · H
 
2
O
16.1.7Lunijianlaite
Li
 
0.7
Al
 
6.2
(AlSi
 
7
lO
 
20
)(OH,O)
 
10
16.1.8Swinefordite
Li(Al,Li,Mg)
 
4
((Si,Al)
 
4
O
 
10
)
 
2
(OH,F)
 
4
 · nH
 
2
O
16.1.9Holmquistite
☐{Li
 
2
}{Mg
 
3
Al
 
2
}(Si
 
8
O
 
22
)(OH)
 
2
16.1.13Clino-holmquistite Group
☐{Li
 
2
}{Z
2+
3
Z
3+
2
}(Si
 
8
O
 
22
)((OH),F,Cl)
 
2
16.1.14Magnesioholmquistite
16.1.15Bityite
LiCaAl
 
2
(AlBeSi
 
2
O
 
10
)(OH)
 
2
16.1.16Sogdianite
K(□,Na)
 
2
Li
 
3
(Zr,Fe,Ti)
 
2
[Si
 
12
O
 
30
]
16.1.17Sugilite
K(Na,□)
 
2
Li
 
3
(Fe,Mn,Al,Zr)
 
2
[Si
 
12
O
 
30
]
Related Minerals - Dana Grouping):

- +
51.1.1.1Phenakite
Be
 
2
SiO
 
4
51.1.1.2Willemite
Zn
 
2
SiO
 
4

Other Names for Eucryptite

Synonyms:
Lithionnephelin
Other Languages:
German:Eucryptit
Russian:Эвкриптит
Simplified Chinese:锂霞石
Spanish:Eucryptita

Other Information

Fluorescence in UV light:Magenta-red or orange under SW UV.
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 Eucryptite

Reference List:

- +
Dana, E.S. (1892) Dana's System of Mineralogy, 6th. edition: 426.

Mrose, M., E., 1953, α-Eucryptite Problem [abstract], American Mineralogist, v. 38. p. 353.

Hurlbut, C.S., Jr. (1962) Eucryptite from Bikita, Southern Rhodesia. American Mineralogist: 47: 557-559.

Leavens, P.B., Hurlbut, C.S., Jr., and Nelen, J.A. (1968) Eucryptite and bikitaite from King's Mountain, North Carolina. American Mineralogist: 53: 1202-1207.

Černý, P. (1972) The Tanco pegmatite at Bernic Lake, Manitoba. VII. Eucryptite. Canadian Mineralogist: 11: 708-713.

Lahti, S.I., Kallio, P., von Knorring, O. (1982): The composition, physical properties and occurrence of eucryptite from the Haapaluoma pegmatite, Finland. Bull.Geol.Soc.Finland, 54, 1-2; 5-13.

Hesse, K.-F. (1985) Crystal structures of natural and synthetic α-eucryptite, LiAlSiO4. Zeitschrift für Kristallographie: 172: 147-151.

Anthony, Bideaux, Bladh & Nichols (1995), Handbook of Mineralogy, Vol. II.

Gaines, Richard V., H. Catherine, W. Skinner, Eugene E. Foord, Brian Mason, Abraham Rosenzweig, Vandall T. King (1997), Dana's New Mineralogy : The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana.

Zeitschrift für Kristallographie: 172: 147-151.

Mindat.org articles about Eucryptite

Article entries:
Chinese Fluorescent Minerals General Report of Xianghualing mine,HuNan,ChinaXiaoJun Chen

Internet Links for Eucryptite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Eucryptite details from Handbook of Mineralogy (PDF)
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    • Localities for Eucryptite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Hide Locality List
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Australia
     
    • Western Australia
      • Coolgardie Shire
        • Nepean
    		M. Jacobson, M. Calderwood, B. Grguric; Pegmatites of Western Australia; (Perth 2007)
    Canada
     
    • Manitoba
      • Lac-du-Bonnet area
        • Bernic Lake
    		Canadian Mineralogist Vol. 15, pp.489-499 (1977); Canadian Mineralogist Vol. 11,pp.591-608 (1972)
    • Ontario
      • Kenora District
    		Tindle, A.G., Breaks, F.W., and Selway, J.B. (2002) Tourmaline in petalite-subtype gramitic pegmatites: evidence of fractionation and contamination from Pakeagama Lake and Separation Lake areas of northwestern Ontario, Canada. Canadian Mineralogist, 40, 753-788.
    China
     
    • Hunan Province
      • Chenzhou Prefecture
        • Linwu Co.
          • Xianghualing Sn-polymetallic ore field
    		Anthony, J.W. et al.: Handbook of Mineralogy
    • Jiangxi Province
      • Yichun Prefecture
        • Yuanzhou District
          • Yichun complex (Yashan batholith)
    		Xudong Che, Rucheng Wang, Huan Hu, Wenlan Zhang, and Xiaolong Huang (2007): Acta Petrologica Sinica 23(6), 1552-1560
    • Xinjiang Autonomous Region
      • Yili Hasake Autonomous Prefecture (Ili Kazakh Autonomous Prefecture)
        • Aletai Prefecture (Altay Prefecture)
          • Fuyun Co. (Koktokay Co.)
            • Koktokay pegmatite field (Keketuohai pegmatite field)
              • Altay Mine
    		Liangming Fan, Yuyuan Mao, Yongwen Wan, and Shiwei Luan (1994): Journal of Mineralogy and Petrology 15(1); Huanzhang Lu, Zhonggang Wang, and Yuansheng Li (1997): Chinese Journal of Geochemistry 16(1), 43-52
    Egypt
     
    • Red Sea Governorate
      • Eastern Desert
    		Gehad M. Saleh (2007) Rare-Metal Pegmatites from the Southeastern Desert, Egypt: Geology, Geochemistry, and Petrogenesis. International Geology Review Vol. 49:824-843.
    Finland
     
    • Western and Inner Finland Region
      • Seinäjoki
        • Peräseinäjoki
    		Lahti, S. I., Kallio, P. and von Knorring, O. (1982): The composition, physical properties and occurrence of eucryptite from the Haapaluoma pegmatite, Finland. Bull.Geol. Soc. Finland 54, 1-2, 5-13.
    Namibia
     
    • Erongo Region
      • Swakopmund District
        • Cape Cross area
    		http://www.mineral.tu-freiberg.de/econgeology/lehre/namibia/snlipegm/snlipegm_2_4.html
    Portugal
     
    • Vila Real District
      • Barroso-Alvão pegmatite field
    		Novák, M. et al. (2009): Ferronigerite with dominant substitution TiSn-1 in muscovite+chlorite aggregate from massive quartz nodule associated with a petalite-rich aplite-pegmatite of the Barroso-Alvão pegmatite field, Northern Portugal. N. Jb. Mineral. Abh. 186, 67-78.
    Russia
     
    • Southern Siberia
      • Sayan Mts
        • Eastern Sayan
    		P.M. Kartashov data
    South Africa
     
    • Northern Cape Province
    		Minerals of South Africa
      • Namaqualand
        • Steinkopf
    		Minerals of South Africa
    Spain
     
    • Castile and Leon
      • Salamanca
        • La Fregeneda
    		Encarnación Roda-Robles, Alfonso Pesquera (2007) Locality no. 3: Lepidolite-spodumene-rich and cassiterite-rich pegmatites from the Feli open-pit, (La Fregeneda, Salamanca, Spain) in ALEXANDRE LIMA & ENCARNACIÓN RODA ROBLES ed (2007) GRANITIC PEGMATITES: THE STATE OF THE ART - FIELD TRIP GUIDEBOOK. MEMÓRIAS N. º 9, UNIV. DO PORTO, FACULDADE DE CIÊNCIAS, DEPARTAMENTO DE GEOLOGIA pp 55-64
    Sweden
     
    • Södermanland
      • Utö
    		Langhof, J., Jonson, E, Gustafsson, L. & Otter, B. (1998): Utö- en klassisk svensk mineralfyndort. Bergverksmuseets Skrift 14, 29-31
    UK
     
    • England
      • Devon
        • Okehampton area (Northern Dartmoor)
    		Fraudulent Kingsbury locality.
    USA
     
    • Arizona
      • Yavapai Co.
    		AmMin 67: 97-113 (1982)
          • Independence Gulch
    		Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 217; London, D. & D.M. Burt (1978), Lithium pegmatites of the White Picacho district, Maricopa and Yavapai Cos., AZ, in D.M. Burt and T.L. Péwé (editors), Guidebook to the geology of central Arizona, AZ Bur. Geol. Min. Tech. Spec. Paper 2: 61-72; London, D. & D.M. Burt (1982b), Lithium aluminosilicate occurrences in pegmatites and the aluminosilicate phase diagram, Am.Min.: 67: 483-509.
    Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 217; London, D. & D.M. Burt (1978), Lithium pegmatites of the White Picacho district, Maricopa and Yavapai Cos., AZ, in D.M. Burt and T.L. Péwé (editors), Guidebook to the geology of central AZ, AZ Bur. Geol. Min. Tech. Spec. Paper 2: 61-72; London, D. & D.M. Burt (1982b), Lithium aluminosilicate occurrences in pegmatites and the aluminosilicate phase diagram, Am.Min.: 67: 483-509.
    • Connecticut
      • Fairfield Co.
        • Town of Ridgefield
          • Branchville
    		Brush and Dana (1880); AmMin 31:329-345 (1946); USGS Prof Paper 255; Rocks & Minerals (1995) 70:396-409; Ronald Januzzi collection
      • Middlesex Co.
        • Portland
          • Collins Hill
            • Strickland pegmatite (Strickland-Cramer Quarry; Strickland-Cramer Mine; Strickland-Cramer Feldspar-Mica Quarries)
    		Januzzi, 1976. Mineral Localities of Connecticut and Southeastern New York State (Taylor Assoc./Mineralogical Press)
    • Maine
      • Oxford Co.
        • Newry
    		King, V. and Foord, E., 1994, Mineralogy of Maine, v. 1.
    • New Hampshire
      • Strafford Co.
        • Strafford
          • Parker Mountain
    		Rocks & Min.:64:504.; Rocks & Minerals 80:4 pp234-241
    • New Mexico
      • Taos Co.
        • Picuris District
    		Northrop, Minerals of New Mexico, 3rd Rev. Ed., 1996; Jahns, R. H. and Ewing, R. C. (1977): The Harding mine, Taos County, New Mexico. Mineralogical Record, 8 (2): 115-126.
    • North Carolina
      • Alexander Co.
    		London,David and Burt,Donald M.,(1982) Lithium Aluminosilicate Occurrences in Pegmatites and the Lithium Aluminosilicate Phase Diagram : American Mineralogist,Vol.67,pg.483-493,1982
      • Cleveland Co.
        • Kings Mountain District
    		Am Min 54 (1969), 1467-1469; Rocks and Minerals, (1985) 60:76-82; Carolina Geological Society Field Trip Guidebook 1981, 39-48
    • South Dakota
      • Custer Co.
        • Custer District
          • Fourmile
    		Rocks & Minerals: 75(3): 156-169.; Staatz, M. H.; Page, L. R.; Norton, J. J.; Wilmarth, V. R. (1963) Exploration for beryllium at the Helen Beryl, Elkhorn, and Tin Mountain pegmatites, Custer County, South Dakota. USGS Prof. Paper 297C.
      • Pennington Co.
        • Keystone District
          • Keystone
    		Rocks & Minerals: 67(6): 380-388.; U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
    Zimbabwe
     
    • Masvingo
      • Bikita Area
    		Zeolites of the World, Rudy W. Tschernich 1992
    Amer.Min.(1958) 43, 768-770
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