IMPORTANT MESSAGE. We need your support now to keep mindat.org running. Click here to find out why.
Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for Educators
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Štěpite

This page is currently not sponsored. Click here to sponsor this page.
Hide all sections | Show all sections

About ŠtěpiteHide

Josef Štěp
Formula:
U(AsO3OH)2 · 4H2O
Colour:
Emerald green
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
3.90 (Calculated)
Crystal System:
Tetragonal
Name:
Named in honour of Josef Štěp (1863-1926), head of the State mines in Jáchymov (1889-1924), who has published with F. Becke in 1904 a study on the occurrence of uranium ores at Jáchymov, and the "father" of the famous Jáchymov radon spa.
Second purely U4+ arsenate mineral after vysokýite. The other U-bearing hydroxyarsanate minerals are chadwickite and 'UM1958-05-AsO:HU', however, both contain U6+ instead of U4+.

The crystal structure is based on sheets of with [8]U and hydroxyarsenate "tetrahedra" perpendicular to [001]; 2/6 oxygens surrounding U atoms belong to the hydroxyarsenate groups, with remaining two oxygens belonging to interlayer water molecules. The UO8 polyhedra are linked to five other U polyhedra via six hydroxyarsenate groups. The [U(AsO3OH)2]0 sheets are linked by hydrogen bonds, that involve interlayer water molecules and sheet-residing OH groups.


Classification of ŠtěpiteHide

Approved
Approval Year:
2012
First Published:
2013

Physical Properties of ŠtěpiteHide

Vitreous
Colour:
Emerald green
Streak:
Gray to greenish gray
Hardness:
Comment:
ca. 2
Tenacity:
Brittle
Cleavage:
Very Good
(001)
Fracture:
Irregular/Uneven
Density:
3.90 g/cm3 (Calculated)
Comment:
density couldn't be measured

Optical Data of ŠtěpiteHide

Type:
Biaxial (-)
RI values:
nα = 1.636(2) nβ = 1.667(3) nγ = 1.672(2)
2V:
Measured: 5° , Calculated: 43°
Max Birefringence:
δ = 0.036
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
2V(meas.) or β possibly incorrect
Pleochroism:
Non-pleochroic
Comments:
anomalous interference - grayish to pale yellow - on the (001) plane

Chemical Properties of ŠtěpiteHide

Formula:
U(AsO3OH)2 · 4H2O
IMA Formula:
U(AsO3OH)2 · 4H2O
Common Impurities:
S

Crystallography of ŠtěpiteHide

Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:
I41/acd
Setting:
I41/acd
Cell Parameters:
a = 10.9894(1) Å, c = 32.9109(6) Å
Ratio:
a:c = 1 : 2.995
Unit Cell V:
3959.7 ų

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
8.190 (100)
7.008 (43)
5.475 (18)
4.111 (16)
3.934 (12)
3.395 (20)
2.933 (18)
2.154 (25)

Type Occurrence of ŠtěpiteHide

General Appearance of Type Material:
crystalline crusts of tabular crystals (the crystals are up to 0.6 mm, showing {001} and {100}), that exist in aggregates up to 6 mm; also blocky intergrowths of crystals; minute radiating aggregates of thin plates
Place of Conservation of Type Material:
Department of Mineralogy and Petrology of the National Museum in Prague, Prague, Czech Republic, catalogue number P1P 7/2011
Geological Setting of Type Material:
at the surface of native arsenic lens, at the joint of Geschieber and Geier veins within Ag-As-Bi-Co-Ni-U hydrothermal vein-type deposit
Associated Minerals at Type Locality:

Synonyms of ŠtěpiteHide

Common AssociatesHide

Associated Minerals Based on Photo Data:
Arsenic3 photos of Štěpite associated with Arsenic on mindat.org.
Vysokýite2 photos of Štěpite associated with Vysokýite on mindat.org.
Arsenolite1 photo of Štěpite associated with Arsenolite on mindat.org.

Fluorescence of ŠtěpiteHide

Other InformationHide

IR Spectrum:
[cm-1]: 3457 + 3392 (OH-stretching of water and
OH); 1652 (v2 (δ) bending of water); 1402 + 1236
(δ(As-OH) bending); 1076, 1035, + 1004 (probably overtones);
936, 869, 853, 830 + 815 [overlapping bands of v(AsO3OH) stretching]; 75
Notes:
Raman bands [cm-1]: 3552 + 3484
(OH-stretching of water and OH); 1641 [v2 (δ) bending
vibration of water]; 1490 + 1239 [δ(As‑OH) bending]; 896 + 844 + 811 [overlapping v(AsO3OH) stretching];
760 [v(As-OH) stretching]; 420, 401, 377, 368, 351,
322, 312 [δ(AsO3OH) bending]; 287, 262,
235 [v(OH-O) stretching]; 180, 160, 139, 115, 107 (lattice modes)
Health Risks:
Radioactive

References for ŠtěpiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Plášil*, J., Fejfarová, K., Hloušek, J., Škoda, R., Novák, M., Sejkora, J., Čejka, J., Veselovský, F., Ondruš, P., Majzlan, J., Mrázek, Z. (2012) Štěpite, IMA 2012-006. page 813; Mineralogical Magazine, 76, 807-817.
Plášil, J.; Fejfarová, K.; Hloušek, J.; Škoda, R.; Novák, M.; Sejkora, J.; Čejka, J.; Dušek, M.; Veselovský, F.; Ondruš, P.; Majzlan, J.Z.; Mrázek, Z. (2013): Štěpite, U(AsO3OH)2.4H2O, from Jáchymov, Czech Republic: the first natural arsenate of tetravalent uranium. Mineral. Mag. 77, 137-152.

Internet Links for ŠtěpiteHide

Localities for ŠtěpiteHide

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
 
  • Karlovy Vary Region
    • Krušné Hory Mts (Erzgebirge)
      • Jáchymov District (St Joachimsthal)
[AmMin 84:688]
          • Svornost Mine (Einigkeit Mine)
Plášil*, J., Fejfarová, K., Hloušek, J., Škoda, R., Novák, M., Sejkora, J., Čejka, J., Veselovský, F., Ondruš, P., Majzlan, J., Mrázek, Z. (2012) Štěpite, IMA 2012-006. page 813; Mineralogical Magazine, 76, 807-817; Plásil, J.; Fejfarová, K.; Hloušek, J.; Skoda, R.; Novák, M.K; Sejkora, J.; Ejka, J.C.; Dusek, M.; Veselovský, F.; Ondrus, P.; Majzlan, J.Z.; Mrazek, Z. (2013): Štěpite, U(AsO3OH)2.4H2O, from Jáchymov, Czech Republic: the first natural arsenate of tetravalent uranium. Mineralogical Magazine 77, 137-152.
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2018, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: October 17, 2018 17:03:39 Page generated: September 16, 2018 14:32:19
Go to top of page