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Howlite

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Big Photo

Bras D'Or Lake Howlite Locality, Iona, Victoria Co., Nova Scotia, Canada
© R. Van Dommelen

Show Howlite Photos (36)



Formula:
Ca
 
2
B
 
5
SiO
 
9
(OH)
 
5
System:MonoclinicColour:White; colourless in ...
Hardness:3½ - 6½
Name:
After Henry How (1828 - 1879) Canadian chemist, geologist, and mineralogist, of Nova Scotia, who first described the species.


Usually compact earthy masses and very rarely in crystals. The earthy material gives a "hardness" of 3.5 but this is just the hardness of separating the grains. The crystals give a hardness of 6.5 (see: http://www.mindat.org/mesg-7-226293.html)

Visit gemdat.org for gemological information about Howlite. Currently in public beta-test.

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:Black's quarry, Brookville farm, Martock, West Hants, 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
Colour:White; colourless in transmitted light
Streak:White
Hardness (Mohs):3½ - 6½
Comment:XLs 6.5; massive 3.5
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:
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
(BSi
 
3
O
 
10
)(OH)
 
6
17.5.2Reedmergnerite
Na[BSi
 
3
O
 
8
]
17.5.3Searlesite
Na(H
 
2
BSi
 
2
O
 
7
)
17.5.4Olenite
Na(Al
 
3
)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
O
 
3
(OH)
17.5.5Elbaite
Na(Li
 
1.5
Al
 
1.5
)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
17.5.6Kalborsite
K
 
6
Al
 
4
BSi
 
6
O
 
20
(OH)
 
4
Cl
17.5.7Boromuscovite
KAl
 
2
(BSi
 
3
O
 
10
)(OH)
 
2
17.5.8Poudretteite
KNa
 
2
B
 
3
Si
 
12
O
 
30
17.5.9Liddicoatite
Ca(Li
 
2
Al)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
17.5.10Datolite
Ca(HBSiO
 
5
)
17.5.11Danburite
CaB
 
2
Si
 
2
O
 
8
17.5.13Bakerite
Ca
 
4
(H
 
5
B
 
5
Si
 
3
O
 
20
)
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
 
12
Mg
 
4
Al(BO
 
3
)
 
3
(SiO
 
4
)
 
4
(CO
 
3
)
 
5
 · H
 
2
O
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
(Ce,Y)
 
2
(Ti
4+
 
,Fe
3+
 
,Al)[B
 
4
Si
 
4
O
 
22
](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
(SiO
 
4
)
 
3
(BO
 
3
)O
 
3
17.5.26Holtite
Al
 
6
(Al,Ta)(SiO
 
4
,SbO
 
4
,AsO
 
4
)
 
3
(BO
 
3
)O
 
3
17.5.27Dravite
Na(Mg
 
3
)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
17.5.28 Ferridravite
17.5.29Axinite-(Mg)
Ca
 
2
MgAl
 
2
BSi
 
4
O
 
15
OH
17.5.30Uvite
Ca(Mg
 
3
)MgAl
 
5
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(F/OH)
17.5.31Garrelsite
Ba
 
3
NaSi
 
2
B
 
7
O
 
16
(OH)
 
4
17.5.32Tienshanite
KNa
 
3
Na
 
6
Ca
 
2
Ba
 
6
Mn
 
6
(Ti
4+
 
,Nb)
 
6
B
 
12
Si
 
36
O
 
114
(O,OH,F)
 
11
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
17.5.37Chromium-dravite
Na(Mg
 
3
)Cr
3+
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
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
BSi
 
4
O
 
15
(OH)
17.5.41Axinite
17.5.42Tinzenite
(CaMn
2+
 
)
 
2
Mn
2+
 
Al
 
2
BSi
 
4
O
 
15
(OH)
17.5.44Schorl
Na(Fe
2+
3
)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
17.5.45Fluor-buergerite
Na(Fe
3+
3
)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
O
 
3
F
17.5.46Feruvite
Ca(Fe
2+
 
)
 
3
MgAl
 
5
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
17.5.47Axinite-(Fe)
Ca
 
2
Fe
2+
 
Al
 
2
BSi
 
4
O
 
15
OH
17.5.48Homilite
Ca
 
2
(Fe
2+
 
,Mg)B
 
2
Si
 
2
O
 
10
17.5.49Grandidierite
(Mg,Fe
2+
 
)(Al,Fe
3+
 
)
 
3
(SiO
 
4
)(BO
 
3
)O
 
2
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
Other Languages:
German:Howlith
Howlit
Khaulit
Silicoborocalcit
Italian:Howlite
Russian:Говлит
Spanish:Howlita
Khaulita
Silicoborocalcita

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, H. (1868): Contributions to the mineralogy of Nova Scotia. III. Borates and other minerals in anhydrite and gypsum. Silicoborocalcite, a new mineral. Philosophical Magazine 35, (4th Ser.), 32-41, 218.
DANA, J.D. (1868): The System of Mineralogy (5th ed.). John Wiley & Sons, New York, N.Y. (598).
PENFIELD, S.L. & SPERRY, E.S. (1887): On the chemical composition of howlite, with a note on the Gooch method for the determination of boracic acid. American Journal of Science 134, 220-223.
FINNEY, J.J., KUMBASAR, I., KONNERT, J.A. & CLARK, J.R. (1970): Crystal structure of the calcium silicoborate, howlite. American Mineralogist 55, 716-728.
GRIFFEN, D.T. (1988): Howlite, Ca2SiB5O9(OH)5: structure refinement and hydrogen bonding. American Mineralogist 73, 1138-1144.
How (1871) Philosophical Magazine and Journal of Science: 41: 270 (as Winkworthite).
Giles (1903) Mineralogical Magazine: 13: 353.
Eakle (1911) University of California Geology Department, Bulletin 6: 179.
Murdoch, Joseph (1957), Crystallography and X-ray measurements of howlite from California: American Mineralogist: 42: 521-524.
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.

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

Joyce, D.K. Gait, R.I. and Sturman, B.D. (1993) Howlite from Iona, Nova Scotia Short paper presented at the Rochester Mineralogical Symposium, Rochester, New York, 1993

Internet Links for Howlite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Howlite details from Handbook of Mineralogy (PDF)
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    • Specimens:The following Howlite specimens are currently listed for sale on minfind.com.
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    • Localities for Howlite

    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.
    Canada
     
    • New Brunswick
      • Kings Co.
        • Cardwell Parish
          • Penobsquis
    		Canadian Mineralogist (1981): 19: 291-301.
        • Hammond Parish
          • Salt Springs evaporite deposit
    		BURNS, P.C., HAWTHORNE, F.C. & STIRLING, J.A.R. (1992): Trembathite, (Mg,Fe)3B7O13Cl, a new borate mineral from the Salt Springs potash deposit, Sussex, New Brunswick. Canadian Mineralogist 30, 445-448.
    • Newfoundland and Labrador
      • Newfoundland
    		Canadian Mineralogist Vol. 13, pp. 370-376 (1975)
    Canadian Mineralogist Vol. 13, pp. 370-376 (1975)
    • Nova Scotia
      • Hants Co.
    		Canadian Mineralogist Vol. 13, pp. 370-376 (1975)
        • West Hants
          • Martock
            • Brookville farm
    		HOW, H. (1868): Contributions to the mineralogy of Nova Scotia. III. Borates and other minerals in anhydrite and gypsum. Silicoborocalcite, a new mineral. Philosophical Magazine 35, (4th Ser.), 32-41, 218. DANA, J.D. (1868): The System of Mineralogy (5th ed.). John Wiley & Sons, New York, N.Y. (598). RAMIK, R.A. (2007) Lost and found: One of Canada’s earliest type mineral localities. Abstracts from the 32rd Rochester Mineralogical Symposium, Rocks & Minerals 82, 244.
      • Victoria Co.
        • Dingwall
    		Canadian Mineralogist Vol. 13, pp. 370-376 (1975)
        • Iona
    		Joyce, D.K. Gait, R.I. and Sturman, B.D. (1993) Howlite from Iona, Nova Scotia Short paper presented at the Rochester Mineralogical Symposium, Rochester, New York, 1993
    Germany
     
    • Lower Saxony
      • Diepholz
    		A. Wittern: "Mineralfundorte in Deutschland", Schweizerbart (Stuttgart), 2001, 23
    • Thuringia
      • Harz
        • Nordhausen
          • Niedersachswerfen
    		Siemroth, J. (2008): Das Vorkommen von Boratmineralien im Werra-Anhydrit des Steinbruchs Kohnstein bei Niedersachswerfen am Südharz, Der Aufschluss, Vol. 59, 353-366
    Mexico
     
    • Sonora
      • Mun. de Magdalena
        • Aguja
    		Garrett, D.E. (1998): Borates - Handbook of Deposits, Processing, Properties and Use. Academic Press (San Diego, London), 475 pp.
      • Mun. de Tubutama
        • La Salada
    		Garrett, D.E. (1998): Borates - Handbook of Deposits, Processing, Properties and Use. Academic Press (San Diego, London), 475 pp.
    Serbia
     
    • Jarandol Basin
      • Balevats
        • Bella Stena (Bela Stena)
    		Econ Geol (1992) 87:2169-2174
    Econ Geol (1992) 87:2169-2174
    S. V. Malinko et al.: New Data on Minerals 39:26-31 (2004); Canadian Mineralogist Vol. 13, pp. 370-376 (1975)
    Slovakia
     
    • Košice Region
      • Rožňava Co.
    		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
          • Faraşköy (Faraş)
    		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 National Park
          • Furnace Creek District (Furnace Creek Borate District)
            • Black Mts
    		Mineralogical Record: 27: 35-40.
              • 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
    Gale, Hoyt Stoddard (1946), Geology of the Kramer borate district, Kern County, California: California Division Mines Report 42: 332; Dibblee, T.W., Jr. (1967a) Areal geology of western Mojave Desert, California. USGS Professional Paper 522: 126-127; Morgan, V. and Erd, R.C. (1969) Minerals of the Kramer borate district, California California Division of Mines and Geology Mineral Information Service: 22(9&10): 152; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 510.
    Gale, Hoyt Stoddard (1946), Geology of the Kramer borate district, Kern County, California: California Division Mines Report 42: 332; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 220.
      • 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
            • Tick Canyon Borate deposit
    		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.; Kramer, H.C. & R.D. Allen (1956), A restudy of bakerite, priceite, and veatchite, American Mineralogist: 41: 689-700; Eakle, Arthur Starr (1911), Neocolemanite, a variety of colemanite, and howlite from Lang, Los Angeles County, California: University of California, Department of Geological Science Bulletin: 6: 187; Foshag, William Frederick (1921), The origin of the colemanite deposits of California: Economic Geology: 16: 204; Allen, Robert D. (1957): 199; Masimer, G.E. (1966) Tick Canyon revisited. Gems and Minerals: 347: 20-23; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 95, 154, 220; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 510.
      • San Bernardino Co.
        • Calico Mts (Calico Hills)
          • Calico District (Daggett District)
            • Borate
    		Giles, W.B. (1903), Bakerite (a new borosilicate of calcium) and howlite from California: Mineralogical Magazine: 13: 353-355; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 95.
    [Murdoch, J & Webb, R (1966) Minerals of California, California Division of Mines and Geology Bulletin 189]
    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.
        • East Kramer District
          • Kramer
            • East Kramer Borate area (East Kramer Colemanite area)
    		Dibblee, Jr., T.W. (1967a) Areal geology of western Mojave Desert, California. USGS Professional Paper 522: 142-146; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 510.
      • Ventura Co.
        • San Emigdio Mts
          • Ventura County Borate District (Stauffer District)
            • Lake of the Woods area
              • Lockwood Valley
    		Gale, Hoyt Stoddard (1914c), Borate deposits in Ventura County, California: USGS Bulletin 540: 442; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 220; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 511.
    • 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.
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