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Howlite

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Bras D'Or Lake, Iona, Cape Breton Island, Victoria Co., Nova Scotia, Canada
© R. Van Dommelen

Show Howlite Photos (13)
Formula:
Ca
 
2
B
 
5
SiO
 
9
(OH)
 
5
System:MonoclinicColour:White; colourless in ...
Hardness:3½
Name:After Henry How (1828 - 1879) Canadian chemist, geologist, and mineralogist, of Nova Scotia, who first described the species.
This page provides mineralogical data about Howlite.

Classification of Howlite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/F.28-10
Nickel-Strunz 10th (pending) edition ID:6.CB.20

6 : BORATES
C : Triborates
B : Ino-triborates
Dana 8th edition ID:25.3.5.1

25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
3 : Triborates
Hey's CIM Ref.:17.5.12

17 : Silicates Containing other Anions
5 : Borosilicates
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Type Occurrence of Howlite

Type Locality:Brookville, Windsor, Hants Co., Nova Scotia, Canada
General Appearance of Type Material:Nodules embedded in anhydrite or gypsum.
Year of Discovery:1868
Associated Minerals at type locality:
UlexiteGypsumAnhydrite

Occurrences of Howlite

Geological Setting:In borate deposits.

Physical Properties of Howlite

Lustre:Sub-Vitreous
Diaphaneity (Transparency):Translucent on thin edges
Colour:White; colourless in transmitted light
Streak:White
Hardness (Mohs):3½
Comment:Even and smooth in porcelaneous types.
Density (measured):2.53 - 2.59 g/cm3
Density (calculated):2.61 g/cm3

Crystallography of Howlite

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:P21/b (P1 1 21/b) [P21/c] {P1 21/c 1} {P21/a}
Cell Parameters:a = 12.82Å, b = 9.351(1) Å, c = 8.608(2) Å
β = 104.84(2)°
Ratio:a:b:c = 1.371 : 1 : 0.921
Unit Cell Volume:V 997.51 ų (Calculated from Unit Cell)
Z:4
Morphology:Compact nodular masses, internally dense and structureless. Chalk-like, earthy, scaly, slaty structured.
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Howlite

Type:Biaxial (-)
RI values: nα = 1.583 - 1.586 nβ = 1.596 - 1.598 nγ = 1.600
2V:Measured: 60° to 90°, Calculated: 88°
Maximum Birefringence:δ = 0.017

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:none

Chemical Properties of Howlite

Formula:
Ca
 
2
B
 
5
SiO
 
9
(OH)
 
5
Essential elements:B, Ca, H, O, Si
All elements listed in formula:B, Ca, H, O, Si
Common Impurities:Na,K

Relationship of Howlite to other Species

Related Minerals - Nickel-Strunz Grouping):
6.CB.10Colemanite
Ca[B
 
3
O
 
4
(OH)
 
3
] · H
 
2
O
6.CB.15Hydroboracite
CaMg[B
 
3
O
 
4
(OH)
 
3
]
 
2
 · 3H
 
2
O
6.CB.25Jarandolite
Ca[B
 
3
O
 
4
(OH)
 
3
]
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
17.5.13Bakerite
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
]
17.5.44Schorl
[Na][Fe
2+
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
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

Other Names for Howlite

Synonyms:
HoweliteKhauliteSilicoborocalciteWinkworthite
German names:
HowlitKhaulitSilicoborocalcit
Russian names:
Говлит
Spanish names:
HowlitaKhaulitaSilicoborocalcita

Other Information

Other Information:Readily soluble in dilute acids. Gelatinous silica results from the reaction upon evaporation.
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 Howlite

Reference List:How (1868) Philosophical Magazine and Journal of Science: 35: 32 (as Silicoborocalcite).

Dana, J.D. (1868) System of Mineralogy, 5th. Edition, New York: 598.

How (1871) Philosophical Magazine and Journal of Science: 41: 270 (as Winkworthite).

Penfield and Sperry (1887) American Journal of Science: 34: 220.

Giles (1903) Mineralogical Magazine: 13: 353.

Eakle (1911) University of California Geology Department, Bulletin 6: 179.

Larsen, E.S. (1921) The Microscopic Determination of the Nonopaque Minerals, First edition, USGS Bulletin 679: 87.

Pabst, Adolf (1938) “Minerals of California,” California Department of Natural Resources, Division of Mines, Geologic Branch, Bulletin 113. 338pp., Sacramento.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 362-363.

Murdoch, Joseph (1957), Crystallography and X-ray measurements of howlite from California: American Mineralogist: 42: 521-524.

Finney, J.J., I. Kumbasar & J.R. Clark (1970), Crystal structure of the calcium silicoborate howlite: American Mineralogist: 55: 716-728.

Papezik, V.S. and Fong, C.C.K. (1975) Howlite and ulexite from the Carboniferous gypsum and anhydrite beds in western Newfoundland. Canadian Mineralogist: 13: 370-376.

American Mineralogist (1988): 73: 1138-1141.

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

Anthony, J.W., Bideaux, R.A., Bladh, K.W., and Nichols, M.C. (2003) Handbook of Mineralogy, Volume V. Borates, Carbonates, Sulfates. Mineral Data Publishing, Tucson, AZ, 813pp.: 349.

Internet Links for Howlite

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    Localities for Howlite

    Hide Locality List
    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.
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    (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.
    Canada
     
    • New Brunswick
      • Kings Co.
        • Sussex
          • Cardwell Parish
            • Penobsquis
    		Canadian Mineralogist (1981): 19: 291-301.
    • Nova Scotia
      • Hants Co.
        • Windsor
    No reference listed
      • Victoria Co.
        • Cape Breton Island
          • Dingwall
          • Iona
    		No reference listed
    Germany
     
    • Lower Saxony
      • Diepholz
    		A. Wittern: "Mineralfundorte in Deutschland", Schweizerbart (Stuttgart), 2001, 23
    Serbia
     
    • Jarandol Basin
      • Balevats
    		S. V. Malinko et al.: New Data on Minerals 39:26-31 (200)
    Slovakia
     
    • Košice Region
      • Eastern Slovenské Rudohorie Mts
    		Koděra, M. et al., 1986 a 1990 : Topografická mineralógia Slovenska, diel 1- 3, Veda – Vydavateľstvo SAV, Bratislava, 1990, 1 – 1590k
    Turkey
     
    • Marmara Region
      • Balikesir Province
        • Bigadiç
    		CAHIT HELVACI & RICARDO N. ALONSO (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, Vol. 9, 2000, pp. 1-27
        • Faras
          • Sultancayin
    		CAHIT HELVACI & RICARDO N. ALONSO (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, Vol. 9, 2000, pp. 1-27
    USA
     
    • California
      • Inyo Co.
        • Death Valley
          • Furnace Creek District
    		Mineralogical Record: 27: 35-40.
            • Black Mts
              • Gower Gulch
    		Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 362.
      • Kern Co.
        • Kramer District
    		www.mineralsocal.org
    Cal Div of Mines & Geology "Mineral Information Service" V. 22 N. 9 Sept 1969
      • Los Angeles Co.
    		Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 362.
          • Tick Canyon
    		Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 348; Rocks & Minerals: 11: 156.
      • San Bernardino Co.
        • Calico-Daggett Borate Area
    		[Murdoch, J & Webb, R (1966) Minerals of California, California Division of Mines and Geology Bulletin 189]
        • Calico Mts
          • Calico District
            • Borate
    Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 362.
    • Nevada
      • Clark Co.
        • Muddy Mountains
          • Muddy Mountains District
    		Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 352.
    Mineral and/or Locality
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