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About NioboholtiteHide

Creamy-white to brownish-yellow or gray-yellow
Specific Gravity:
3.72 (Calculated)
Crystal System:
For the mineral holtite and its niobium content.
This is Nb-analogue of titanoholtite. Nioboholtite is also the second mineral, after schiavinatoite, with essential Nb and B.

Classification of NioboholtiteHide


Physical Properties of NioboholtiteHide

Creamy-white to brownish-yellow or gray-yellow
3.72 g/cm3 (Calculated)

Optical Data of NioboholtiteHide

Biaxial (-)
RI values:
nα = 1.740 - 1.747 nβ = 1.760 nγ = 1.760
Max Birefringence:
δ = 0.020
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of NioboholtiteHide

IMA Formula:
Common Impurities:

Crystallography of NioboholtiteHide

Crystal System:
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Cell Parameters:
a = 47.001 Å, b = 11.828 Å, c = 20.243 Å
a:b:c = 3.974 : 1 : 1.711
Unit Cell V:
11,253.65 ų (Calculated from Unit Cell)

X-Ray Powder DiffractionHide

Powder Diffraction Data:
From Type Description.

Type Occurrence of NioboholtiteHide

Place of Conservation of Type Material:
Mineralogical Museum of the University of Wrocław, Wrocław, Poland, catalogue number MMWr IV7615; cotype specimens are deposited in the same Museum, catalogue numbers MMWr IV7616, MMWr IV7617, MMWr IV7618 and MMWr IV7619, and in the collections of the Smi
Geological Setting of Type Material:
Szklary serpentinite massif, c. 60 km south of Wrocław, Lower Silesia, Poland (50º39.068’N 16º49.932’E)
Associated Minerals at Type Locality:

Synonyms of NioboholtiteHide

Relationship of Nioboholtite to other SpeciesHide

Other Members of this group:
Holtite(Ta0.60.4)Al6BSi3O18(O,OH)2.25Orth. mmm (2/m 2/m 2/m) : Pnma
Titanoholtite(Ti0.750.25)Al6BSi3O18Orth. mmm (2/m 2/m 2/m) : Pbcm

Common AssociatesHide

Associated Minerals Based on Photo Data:
Holtite1 photo of Nioboholtite associated with Holtite on mindat.org.
Titanoholtite1 photo of Nioboholtite associated with Titanoholtite on mindat.org.

Other InformationHide

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 NioboholtiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Pieczka, A., Evans, R.J., Grew, E.S., Groat, L.A., Ma, C., Rossman, G.R. (2013) Nioboholtite, IMA 2012-068. CNMNC Newsletter No. 15, February 2013, page 7; Mineralogical Magazine: 77: 1-12.
Pieczka, A., Evans, R.J., Grew, E.S., Groat, L.A., Ma, C.,, Rossman, G.R. (2013a) The dumortierite supergroup. II. Three new minerals from the Szklary pegmatite, SW Poland: Nioboholtite, (Nb0.6◻0.4)Al6BSi3O18, titanoholtite, (Ti0.75◻0.25)Al6BSi3O18, and szklaryite, ◻Al6BAs3+3O15. Mineralogical Magazine: 77(6): 2841-2856.

Internet Links for NioboholtiteHide

Localities for NioboholtiteHide

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.
Poland (TL)
  • Lower Silesia
    • Ząbkowice Slaskie District
      • Ząbkowice (Frankenstein)
        • Szklary (Gläsendorf)
Pieczka, A., Evans, R.J., Grew, E.S., Groat, L.A., Ma, C. and Rossman, G.R. (2013) Nioboholtite, IMA 2012-068. CNMNC Newsletter No. 15, February 2013, page 7; Mineralogical Magazine, 77, 1-12.; Pieczka, A., Evans, R. J., Grew, E. S., Groat, L. A., Ma, C., & Rossman, G. R. (2013). The dumortierite supergroup. II. Three new minerals from the Szklary pegmatite, SW Poland: Nioboholtite,(Nb0. 6⃞0. 4) Al6BSi3O18, titanoholtite,(Ti0. 75⃞0. 25) Al6BSi3O18, and szklaryite, ⃞Al6BAs33+ O15. Mineralogical Magazine, 77(6), 2841-2856.
Mineral and/or Locality  
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