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Tvrdýite

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About TvrdýiteHide

Jaromír Tvrdý
Formula:
Fe2+Fe3+2 Al3(PO4)4(OH)5(H2O)4·2H2O
Colour:
Silvery to olive-greyish-green
Lustre:
Pearly
Hardness:
3 - 4
Specific Gravity:
2.834 (Calculated)
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Jaromír Tvrdý (b. 1959) from Liberec, Czech Republic, for his contributions to mineralogy and economic geology.
Isostructural with:
Isostructural with beraunite. Chemically similar to cacoxenite, childrenite, ferrivauxite, metavauxite, paravauxite, sigloite, and vauxite; also matulaite.

The type material is significantly enriched in Zn.

Difference from beraunite: Al dominance in 2/4 M sites.


Classification of TvrdýiteHide

Approved
Approval Year:
2014
First Published:
2016

Physical Properties of TvrdýiteHide

Pearly
Colour:
Silvery to olive-greyish-green
Streak:
Greyish-white
Hardness:
3 - 4 on Mohs scale
Comment:
ca. 3-4
Tenacity:
Very brittle
Cleavage:
Distinct/Good
{100}
Comment:
fibres are somewhat flexible
Density:
2.834 g/cm3 (Calculated)

Optical Data of TvrdýiteHide

Type:
Biaxial (-)
RI values:
nα = 1.650(2) nβ = 1.671(1) nγ = 1.677(1)
2V:
Measured: 56° (1)
Max Birefringence:
δ = 0.027
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
High
Dispersion:
strong (r > v)
Comments:
Greenish-blue (X), yellowish-orange (Y, Z); X >> Y > Z

Chemical Properties of TvrdýiteHide

Formula:
Fe2+Fe3+2 Al3(PO4)4(OH)5(H2O)4·2H2O
IMA Formula:
Fe2+Fe3+2Al3(PO4)4(OH)5(H2O)4 · 2H2O
Common Impurities:
Zn,As,F

Crystallography of TvrdýiteHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 20.564(4) Å, b = 5.101(1) Å, c = 18.883(4) Å
β = 93.68(3)°
Ratio:
a:b:c = 4.031 : 1 : 3.702
Unit Cell V:
1976.7 ų
Z:
4
Morphology:
acicular to fibrous crystals 0.5 - 5 μm in diameter and up to 300 μm long; may be in radiating aggregates, up to 3 mm

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
10.227(100)
9.400(6)
7.156(14)
5.120(7)
3.416(11)
3.278(6)
2.562(5)
2.051(3)
Comments:
From Type Description.

Type Occurrence of TvrdýiteHide

General Appearance of Type Material:
acicular to fibrous; radiating aggregates
Place of Conservation of Type Material:
Type material is housed in the collections of the Department of Mineralogy and Petrology, National Museum Prague, Cirkusova´ 1740, CZ- 193 00 Prague 9, Czech Republic, catalogue number P1P 11/2014
Geological Setting of Type Material:
cavity in quartz gangue
Associated Minerals at Type Locality:
Reference:
Sejkora, J., Grey, I.E., Kampf, A.R., Price, J.R., Cejka, J. (2016) Tvrdýite, Fe2+Fe3+2Al3(PO4)4(OH)5(OH2)4·2H2O, a new phosphate mineral from Krásno near Horní Slavkov, Czech Republic. Mineralogical Magazine: 80: 1077-1088.

Synonyms of TvrdýiteHide

Relationship of Tvrdýite to other SpeciesHide

Member of:
Other Members of this group:
BerauniteFe2+Fe3+5(PO4)4(OH)5 · 6H2OMon. 2/m : B2/b
EleonoriteFe3+6(PO4)4O(OH)4 · 6H2OMon. 2/m : B2/b
ZincoberauniteZnFe3+5(PO4)4(OH)5·6H2OMon. 2/m : B2/b

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 TvrdýiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Sejkora, J., Grey, I.E., Kampf, A.R. and Price, J.R. (2015) Tvrdýite, IMA 2014-082. CNMNC Newsletter No. 23, February 2015, page 57. Mineralogical Magazine: 79: 51-58.
Sejkora, J., Grey, I.E., Kampf, A.R., Price, J.R., Cejka, J. (2016) Tvrdýite, Fe2+Fe3+2Al3(PO4)4(OH)5(OH2)4·2H2O, a new phosphate mineral from Krásno near Horní Slavkov, Czech Republic. Mineralogical Magazine: 80: 1077-1088.
Cámara, F., Belakovskiy, D.I., Uvarova, Y. (2017) New mineral names. American Mineralogist: 102: 916-920.

Internet Links for TvrdýiteHide

Localities for TvrdýiteHide

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.
Czech Republic (TL)
 
  • Karlovy Vary Region
    • Horní Slavkov (Schlaggenwald)
      • Krásno (Schönfeld)
Sejkora, J., Grey, I.E., Kampf, A.R. and Price, J.R. (2015) Tvrdýite, IMA 2014-082. CNMNC Newsletter No. 23, February 2015, page 57; Mineralogical Magazine, 79, 51-58.
Germany
 
  • Bavaria
    • Upper Palatinate
      • Waidhaus
        • Hagendorf
Weiß, S. & Hochleitner, R. (2017): Neue Mineralien aus Hagendorf. Lapis 42 (9), 42-46; 92. (p. 44; analysed by Nikita Chukanov)
Mineral and/or Locality  
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