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About AmmonioboriteHide

(NH4)2[B5O6(OH)4]2 · H2O
White; colourless in transmitted light
Specific Gravity:
Crystal System:
In allusion to the composition, containing AMMONIum and being a BORate.
Dimorph of:
Microscopic plates, grouped in parallel; commonly as fine-grained granular masses.

Classification of AmmonioboriteHide

Approved, 'Grandfathered' (first described prior to 1959)

E : Pentaborates
A : Neso-pentaborates

5 : Pentaborates

9 : Borates
1 : Borates of the alkalis and boric acid

Pronounciation of AmmonioboriteHide

PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of AmmonioboriteHide

White; colourless in transmitted light
None Observed
1.765(4) g/cm3 (Measured)    1.76 g/cm3 (Calculated)

Optical Data of AmmonioboriteHide

Biaxial (+)
RI values:
nα = 1.470 nβ = 1.487 nγ = 1.540
Measured: 60° , Calculated: 62°
Max Birefringence:
δ = 0.070
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
relatively weak

Chemical Properties of AmmonioboriteHide

(NH4)2[B5O6(OH)4]2 · H2O
IMA Formula:
(NH4)3B15O20(OH)8 · 4H2O

Crystallography of AmmonioboriteHide

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Cell Parameters:
a = 25.27 Å, b = 9.65 Å, c = 11.56 Å
β = 94.29°
a:b:c = 2.619 : 1 : 1.198
Unit Cell V:
2,811.07 ų (Calculated from Unit Cell)
Compact, fine-grained masses. Partially as platy microscopic crystals, frequently grouped in parallel position.

Type Occurrence of AmmonioboriteHide

Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 93756, 94172, R6167.
Geological Setting of Type Material:
Boric acid fumaroles in a volcanic region. In boric acid-rich fumarolic lagoons.
Associated Minerals at Type Locality:

Other Language Names for AmmonioboriteHide

Related Minerals - Nickel-Strunz GroupingHide

6.EA.05SborgiteNa[B5O6(OH)4] · 3H2OMon.
6.EA.05LeucostauritePb2[B5O9]Cl · 0.5H2OOrth. mm2 : Pnn2
6.EA.10SantiteK[B5O6(OH)4] · 2H2OOrth.
6.EA.10Ramanite-(Rb)Rb[B5O6(OH)4] · 2H2OOrth. mm2 : Aba2
6.EA.10Ramanite-(Cs)Cs[B5O6(OH)4] · 2H2OMon. 2/m : B2/b
6.EA.25UlexiteNaCa[B5O6(OH)6] · 5H2OTric. 1 : P1

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

9.1.1SassoliteH3BO3Tric. 1 : P1
9.1.4BiringucciteNa2B5O8(OH) · H2OMon.
9.1.5NasiniteNa2[B5O8(OH)] · 2H2OOrth.
9.1.6KerniteNa2[B4O6(OH)2] · 3H2OMon. 2/m : P2/b
9.1.7EzcurriteNa4B10O17 · 7H2OTric. 1 : P1
9.1.8TincalconiteNa2(B4O7) · 5H2OTrig. 3 2 : R3 2
9.1.9BoraxNa2(B4O5)(OH)4 · 8H2OMon. 2/m : B2/b
9.1.11SborgiteNa[B5O6(OH)4] · 3H2OMon.
9.1.12AristarainiteNa2MgB12O20 · 8H2OMon. 2/m : P21/b
9.1.13SantiteK[B5O6(OH)4] · 2H2OOrth.
9.1.14Larderellite(NH4)B5O7(OH)2 · H2OMon.
9.1.16Rhodizite(K,Cs)Al4Be4(B,Be)12O28Iso. 4 3m : P4 3m

Other InformationHide

Slowly and completely soluble in cold water.
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 AmmonioboriteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Sborgi and Meccacci (1916) Reale accademia nazionale dei Lincei, Rome, Att.: 25: 455.
Schaller, W.T. (1931) Ammonioborite, a new mineral. in: Proceedings of the eleventh annual meeting of the Mineralogical Society of America at Toronto, Canada. American Mineralogist: 16: 107-119.
D'Achiardi (1932) Periodico de Mineralogia-Roma: 3: 36.
Schaller, W.T. (1933) Ammonioborite, a new mineral. American Mineralogist: 18: 480-492.
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: 366-367.
Clark, J.R., Christ, C.L. (1959) Studies of borate minerals (VII): X-Ray studies of ammonioborite, larderellite, and the potassium and ammonium pentaborate tetrahydrates. American Mineralogist: 44: 1150-1158.
Merlino, S., Sartori, F. (1971) Ammonioborite: New borate polyion and its structure. Science: 171: 377-379.
Anderson, J.E., Bubnova, R.S., Filatov, S.K., Ugolkov, V.L., Britvin, S.N. (2009) Thermal investigation of ammonioborite (NH4)3[B15O20(OH)8]•4H2O. Glass Physics and Chemistry: 35: 191-198.

Internet Links for AmmonioboriteHide

Localities for AmmonioboriteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Italy (TL)
  • Tuscany
    • Pisa Province
      • Pomarance
D'Achiardi G. (1932): Considerazioni e ricerche sulla larderellite, ammonioborite (?) e bechilite (?) di Larderello (Pisa). Periodico di Mineralogia - Roma pp. 36-42; 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: 366; Chukanov, N.V. (2014) Infrared spectroscopy of minerals. Extended library. Volume 1. Springer, Dordrecht Heidelberg New York London, pages 73 and 75.
Mineral and/or Locality  
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