Hydroxylborite
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About Hydroxylborite
Formula:
Mg3(BO3)(OH)3
Colour:
Colourless
Lustre:
Vitreous
Hardness:
3½
Specific Gravity:
2.89
Crystal System:
Hexagonal
Name:
In allusion to its composition, being the HYDROXYL dominant member of the series with fluoBORITE.
Type Locality:
Isostructural with:
Classification of Hydroxylborite
Approved
Approval Year:
2007
6.AB.50
6 : BORATES
A : Monoborates
B : BO3, with additional anions; 1(D) + OH, etc.
6 : BORATES
A : Monoborates
B : BO3, with additional anions; 1(D) + OH, etc.
Physical Properties of Hydroxylborite
Vitreous
Transparency:
Transparent
Colour:
Colourless
Streak:
White
Hardness:
3½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Imperfect/Fair
On {0001}, imperfect.
On {0001}, imperfect.
Density:
2.89 g/cm3 (Measured) 2.872 g/cm3 (Calculated)
Optical Data of Hydroxylborite
Type:
Uniaxial (-)
RI values:
nω = 1.566 nε = 1.531
Max Birefringence:
δ = 0.035

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Chemical Properties of Hydroxylborite
Formula:
Mg3(BO3)(OH)3
Elements listed:
Crystallography of Hydroxylborite
Crystal System:
Hexagonal
Class (H-M):
6/m - Dipyramidal
Space Group:
P63/m
Cell Parameters:
a = 8.912 Å, c = 3.112 Å
Ratio:
a:c = 1 : 0.349
Unit Cell V:
214.05 ų
Z:
2
Morphology:
Crystals prismatic with dominant {1100} and without distinct terminal faces; also occurs as radial aggregates.
Type Occurrence of Hydroxylborite
Place of Conservation of Type Material:
Fersman Mineralogical Museum, Moscow (#91968), and the Geology Museum of the All-Russian Scientific Research Institute of Mineral Resources (#M-1663).
Associated Minerals at Type Locality:
Synonyms of Hydroxylborite
Relationship of Hydroxylborite to other Species
Forms a series with:
Related Minerals - Nickel-Strunz Grouping
6.AB.05 | Hambergite | Be2(BO3)(OH) | Orth. mmm (2/m 2/m 2/m) : Pbca |
6.AB.10 | Berborite | Be2(BO3)(OH,F) · H2O | Trig. |
6.AB.15 | Jeremejevite | Al6(BO3)5(F,OH)3 | Hex. 6/m : P63/m |
6.AB.20 | Warwickite | (Mg,Ti,Fe,Cr,Al)2O(BO3) | Orth. |
6.AB.20 | Yuanfuliite | Mg(Fe3+,Al)O(BO3) | Orth. |
6.AB.25 | Karlite | Mg7(BO3)3(OH,Cl)5 | Orth. |
6.AB.30 | Azoproite | (Mg,Fe2+)2(Fe3+,Ti,Mg)(BO3)O2 | Orth. |
6.AB.30 | Bonaccordite | Ni2Fe3+(BO3)O2 | Orth. |
6.AB.30 | Fredrikssonite | Mg2(Mn3+,Fe3+)(BO3)O2 | Orth. |
6.AB.30 | Ludwigite | Mg2Fe3+(BO3)O2 | Orth. |
6.AB.30 | Vonsenite | Fe2+2Fe3+(BO3)O2 | Orth. |
6.AB.35 | Pinakiolite | (Mg,Mn2+)2Mn3+(BO3)O2 | Mon. |
6.AB.40 | Blatterite | Sb5+(Mn3+,Fe3+)9(Mn2+,Mg)35(BO3)16O32 | Orth. mmm (2/m 2/m 2/m) : Pnnm |
6.AB.40 | Chestermanite | Mg2(Fe3+,Mn3+,Al,Sb3+)(BO3)O2 | Orth. |
6.AB.40 | Orthopinakiolite | (Mg,Mn2+)2Mn3+(BO3)O2 | Orth. |
6.AB.40 | Takéuchiite | (Mg,Mn2+)2(Mn3+,Fe3+)(BO3)O2 | Orth. |
6.AB.45 | Hulsite | (Fe2+,Mg)2(Fe3+,Sn)(BO3)O2 | Mon. |
6.AB.45 | Magnesiohulsite | (Mg,Fe2+)2(Fe3+,Sn,Mg)(BO3)O2 | Mon. |
6.AB.45 | Aluminomagnesiohulsite | (Mg,Fe2+)2(Al,Mg,Sn)(BO3)O2 | Mon. 2/m |
6.AB.50 | Fluoborite | Mg3(BO3)(F,OH)3 | Hex. |
6.AB.55 | Shabynite | Mg5(BO3)(OH)5(Cl,OH)2 · 4H2O | Mon. |
6.AB.55 | Wightmanite | Mg5(BO3)O(OH)5 · 2H2O | Mon. |
6.AB.60 | Gaudefroyite | Ca4Mn3+2-3(BO3)3(CO3)(O,OH)3 | Hex. |
6.AB.65 | Sakhaite | Ca12Mg4(BO3)7(CO3)4(OH)2Cl | Iso. m3m (4/m 3 2/m) : Fd3m |
6.AB.70 | Harkerite | Ca12Mg4Al(BO3)3(SiO4)4(CO3)5 · H2O | Trig. 3m (3 2/m) : R3m |
6.AB.75 | Pertsevite-(F) | Mg2(BO3)(F,OH) | Orth. mm2 : Pna21 |
6.AB.75 | Pertsevite-(OH) | Mg2(BO3)(OH) | Orth. mmm (2/m 2/m 2/m) : Pnma |
6.AB.80 | Jacquesdietrichite | Cu2(H2BO3)(OH)3 | Orth. mmm (2/m 2/m 2/m) : Pmna |
6.AB.85 | Painite | CaZrAl9(BO3)O15 | Hex. |
Other Information
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 Hydroxylborite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Rudnev, V.V., Chukanov, N.V., Nechelyustov, G.N., Yamnova, N.A. (2007): Hydroxylborite, Mg3(BO3)(OH)3, a new mineral, and the isomorphous fluoborite-hydroxylborite series. Proceedings of the Russian Mineralogical Society, 136(1), 69-82.
Internet Links for Hydroxylborite
mindat.org URL:
https://www.mindat.org/min-31567.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
Localities for Hydroxylborite
Locality List




All localities listed without proper references should be considered as questionable.
Russia | |
| The Chersky Range is within the Saha Republic which does list hydroxylborite. This is the TL. |
| Rudnev, V.V., Chukanov, N.V., Nechelyustov, G.N., Yamnova, N.A. (2007): Hydroxylborite, Mg3(BO3)(OH)3, a new mineral, and the isomorphous fluoborite-hydroxylborite series. Proceedings of the Russian Mineralogical Society, 136(1), 69-82. |
Chersky Range, Sakha Republic, Russia