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Howlite

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Henry How
Formula:
Ca2B5SiO9(OH)5
System:
Monoclinic
Colour:
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.

Classification of Howlite

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
6.CB.20

6 : BORATES
C : Triborates
B : Ino-triborates
25.3.5.1

25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
3 : Triborates
17.5.12

17 : Silicates Containing other Anions
5 : Borosilicates
mindat.org URL:
http://www.mindat.org/min-1936.html
Please feel free to link to this page.

Type Occurrence of Howlite

General Appearance of Type Material:
Nodules embedded in anhydrite or gypsum.
Year of Discovery:
1868
Associated Minerals at Type Locality:

Occurrences of Howlite

Geological Setting:
In borate deposits.

Physical Properties of Howlite

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:
2.53 - 2.59 g/cm3 (Measured)    2.61 g/cm3 (Calculated)

Crystallography of Howlite

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
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:
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°
Max Birefringence:
δ = 0.017
Image 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:
Ca2B5SiO9(OH)5
Essential elements:
All elements listed in formula:
Common Impurities:
Na,K

Relationship of Howlite to other Species

6.CB.10ColemaniteCa[B3O4(OH)3] · H2O
6.CB.15HydroboraciteCaMg[B3O4(OH)3]2 · 3H2O
6.CB.25JarandoliteCa[B3O4(OH)3]
17.5.1ManandoniteLi2Al4(Si2AlB)O10(OH)8
17.5.2ReedmergneriteNa[BSi3O8]
17.5.3SearlesiteNa(H2BSi2O7)
17.5.4OleniteNa(Al3)Al6(Si6O18)(BO3)3O3(OH)
17.5.5ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.6KalborsiteK6Al4BSi6O20(OH)4Cl
17.5.7BoromuscoviteKAl2(BSi3O10)(OH)2
17.5.8PoudretteiteKNa2B3Si12O30
17.5.9LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.10DatoliteCa(HBSiO5)
17.5.11DanburiteCaB2Si2O8
17.5.13BakeriteCa4(H5B5Si3O20)
17.5.14OyeliteCa10Si8B2O29 · 12.5H2O
17.5.15KornerupineMg3Al6(Si,Al,B)5O21(OH)
17.5.16HarkeriteCa12Mg4Al(BO3)3(SiO4)4(CO3)5 · H2O
17.5.17Serendibite(Ca,Na)2(Mg,Fe2+)3(Al,Fe3+)3[O2|(Si,Al,B)6O18]
17.5.18Stillwellite-(Ce)(Ce,La,Ca)BSiO5
17.5.19Tadzhikite-(Ce)(Ca,Ce)4(Ce,Y)2(Ti4+,Fe3+,Al)[B4Si4O22](OH)2
17.5.20Melanocerite-(Ce)(Ce,Ca)5(SiO4,BO4)3(OH,0)
17.5.21Okanoganite-(Y)(Na,Ca)3(Y,Ce)12Si6B2O27F14
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)6Si3B6O24F2
17.5.25Dumortierite(Al,Fe3+)7(SiO4)3(BO3)O3
17.5.26Holtite(Ta0.60.4)Al6BSi3O18(O,OH)2.25
17.5.27DraviteNa(Mg3)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.28 Ferridravite
17.5.29Axinite-(Mg)Ca2MgAl2BSi4O15OH
17.5.30UviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3(F/OH)
17.5.31GarrelsiteBa3NaSi2B7O16(OH)4
17.5.32TienshaniteKNa3Na6Ca2Ba6Mn6(Ti4+,Nb)6B12Si36O114(O,OH,F)11
17.5.33LeucospheniteBaNa4Ti2B2Si10O30
17.5.34TaramelliteBa4(Fe3+,Ti,Fe2+,Mg)4(B2Si8O27)O2Clx
17.5.35TitantaramelliteBa4(Ti,Fe3+,Fe2+,Mg)4(B2Si8O27)O2Clx
17.5.36NagashimaliteBa4(V,Ti)4B2Si8O27(O,OH)2Cl
17.5.37Chromium-draviteNa(Mg3)Cr63+(Si6O18)(BO3)3(OH)3(OH)
17.5.38WawayandaiteCa6Mn2BBe9Si6O23(OH,Cl)15
17.5.39Werdingite(Mg,Fe)2Al14Si4B4O37
17.5.40Axinite-(Mn)Ca2Mn2+Al2BSi4O15(OH)
17.5.41Axinite
17.5.42Tinzenite(Ca,Mn2+)2Mn2+Al2BSi4O15(OH)
17.5.44SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.45Fluor-buergeriteNa(Fe33+)Al6(Si6O18)(BO3)3O3F
17.5.46FeruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3(OH)
17.5.47Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
17.5.48HomiliteCa2(Fe2+,Mg)B2Si2O10
17.5.49Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
17.5.50Hyalotekite(Pb,Ba,K)4(Ca,Y)2(B,Be)2(Si,B)2Si8O28(F,Cl)
17.5.51Hellandite-(Y)(Ca,REE)4Y2Al(Be,Li)2-xB4Si4O22(OH)2

Other Names for Howlite

Other Information

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

Specimens:
The following Howlite specimens are currently listed for sale on minfind.com.

Localities for Howlite

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.
(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? 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
 
  • Raška District
    • Raška
      • Jarandol Basin
        • Baljevac na Ibru
          • 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
      • Susurluk
        • Sultançayırı (Sultan Tschair)
CAHIT HELVACI & RICARDO N. ALONSO (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, 9:1-27.; Helvaci, C. (1994). Mineral assemblages and formation of the Kestelek and Sultancayir borate deposits. Proc. 29th Intl. Geol. Congr. Part A, 245-284.; Helvaci, C., Mordogan, H., Çolak, M., & Gündogan, I. (2004). Presence and distribution of lithium in borate deposits and some recent lake waters of west-central Turkey. International Geology Review, 46(2), 177-190.
UK
 
  • England
    • North Yorkshire
Smith, F.W., Dearlove, J.P.L., Kemp, S.J., Bell, C.P., Milne, C.J. and Pottas, T.L. (2014) Potash – Recent exploration developments in North Yorkshire. Pp. 45-50 in Hunger, E., Brown, T. J. and Lucas, G. (Eds.) Proceedings of the 17th Extractive Industry Geology Conference, EIG Conferences Ltd. 202pp
Smith, F.W., Dearlove, J.P.L., Kemp, S.J., Bell, C.P., Milne, C.J. and Pottas, T.L. (2014) Potash – Recent exploration developments in North Yorkshire. Pp. 45-50 in Hunger, E., Brown, T. J. and Lucas, G. (Eds.) Proceedings of the 17th Extractive Industry Geology Conference, EIG Conferences Ltd. 202pp
Smith, F.W., Dearlove, J.P.L., Kemp, S.J., Bell, C.P., Milne, C.J. and Pottas, T.L. (2014) Potash – Recent exploration developments in North Yorkshire. Pp. 45-50 in Hunger, E., Brown, T. J. and Lucas, G. (Eds.) Proceedings of the 17th Extractive Industry Geology Conference, EIG Conferences Ltd. 202pp
USA
 
  • California
    • Inyo Co.
      • Amargosa Range
        • Black Mts
          • Zabriskie Point
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.
      • Furnace Creek District (Furnace Creek Borate District; Death Valley Area Borate Deposits; Ryan area)
        • Ryan
Mineralogical Record: 27: 35-40.
    • 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 Mts
        • 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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