Scordariite
A valid IMA mineral species
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About Scordariite
Formula:
K8(Fe3+0.67◻0.33)[Fe3+3O(SO4)6]2 · 14H2O
Colour:
Yellowish to brownish
Lustre:
Vitreous
Hardness:
2 - 2½
Specific Gravity:
2.432 (Calculated)
Crystal System:
Trigonal
Name:
Named in honor of Fernando Scordari (b. 1944), professor of Mineralogy at the University of Bari. He was the president of the Società Italiana di Mineralogia e Petrologia (SIMP) in 1998–2000 and a vice-president of the European Mineralogical Union (2000–2004). He is an expert on crystallography and mass spectrometry with special interest in silicates and sulfates. He also made important contributions to the crystal chemistry of metavoltine and its related compounds.
Structurally related to metavoltine and carlsonite. Chemically especially related to giacovazzoite - another K-Fe oxysulfate.
Unique Identifiers
Mindat ID:
53674
Long-form identifier:
mindat:1:1:53674:1
IMA Classification of Scordariite
Approved
IMA Formula:
K8(Fe3+0.67◻0.33)[Fe3+3O(S6+O4)6(H2O)3]2(H2O)11
Approval year:
2019
First published:
2019
Type description reference:
Classification of Scordariite
7.DF.52
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Sda | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Scordariite
Vitreous
Transparency:
Transparent
Colour:
Yellowish to brownish
Streak:
Yellowish
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{0001}
{0001}
Fracture:
Irregular/Uneven
Density:
2.432 g/cm3 (Calculated)
Optical Data of Scordariite
Type:
Uniaxial (-)
Pleochroism:
Visible
Comments:
pale yellow to yellow
Comments:
Mean refractive index is 1.573.
Chemistry of Scordariite
Mindat Formula:
K8(Fe3+0.67◻0.33)[Fe3+3O(SO4)6]2 · 14H2O
Element Weights:
Crystallography of Scordariite
Crystal System:
Trigonal
Class (H-M):
3 - Rhombohedral
Space Group:
R3
Cell Parameters:
a = 9.7509(4) Å, c = 53.525(2) Å
Ratio:
a:c = 1 : 5.489
Unit Cell V:
4,407.34 ų (Calculated from Unit Cell)
Z:
3
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.8 Å | (mw) |
| 8.3 Å | (s) |
| 6.6 Å | (m) |
| 4.22 Å | (m) |
| 3.777 Å | (m) |
| 3.299 Å | (m) |
| 3.189 Å | (m) |
| 2.884 Å | (s) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Scordariite
General Appearance of Type Material:
Pseudo-hexagonal {0001} tabular crystals up to 0.5 mm in size
Place of Conservation of Type Material:
Mineralogical collections of the Museo di Storia Naturale, Università di Pisa, Via Roma 79, Calci (Pisa, Italy), catalogue number 19893
Geological Setting of Type Material:
Oxidation of pyrite in old stopes.
Associated Minerals at Type Locality:
Synonyms of Scordariite
Other Language Names for Scordariite
Dutch:Scordariiet
German:Scordariit
Common Associates
Associations Based on Photo Data:
| 7 photos of Scordariite associated with Giacovazzoite | K5Fe3+3O(SO4)6 · 10H2O |
Related Minerals - Strunz-mindat Grouping
| 7.DF. | Siligiite | [Pb(H2O)5(SO4)][Zn9(OH)18] |
| 7.DF. | Alcaparrosaite | K3Ti4+Fe3+(SO4)4O(H2O)2 |
| 7.DF. | Flaggite | Pb4Cu2+4Te6+2(SO4)2O11(OH)2(H2O) |
| 7.DF. | Bairdite | Pb2Cu2+4Te6+2O10(OH)2(SO4) · H2O |
| 7.DF. | Tzeferisite | CaZn8(SO4)2(OH)12Cl2(H2O)9 |
| 7.DF. | Cherokeeite | [Pb2Zn(OH)4](SO4) · H2O |
| 7.DF. | Ammoniomathesiusite | (NH4)5(UO2)4(SO4)4(VO5) · 4H2O |
| 7.DF. | Sigogglinite | [Pb6Zn(OH)8]2(SO4)6 · (H2O)8-x |
| 7.DF.X | Blueridgeite | [Pb8Zn3Cu2+(OH)16](SO4)2(S2O3)2 · 2H2O |
| 7.DF. | Erssonite | Mg7Fe3+2(OH)18[Ca(H2O)6](SO4)2 · 12H2O |
| 7.DF. | Poellmannite | Ca6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2O |
| 7.DF. | Carlsonite | (NH4)5Fe3+3O(SO4)6 · 7H2O |
| 7.DF. | Cuprocherokeeite | [Pb8Zn3Cu2+(OH)16](SO4)4 · 4H2O |
| 7.DF. | Haywoodite | [Pb(H2O)10][Zn12(OH)20(H2O)(SO4)3] |
| 7.DF. | Chromschieffelinite | Pb10Te6+6O20(OH)14(CrO4)(H2O)5 |
| 7.DF.05 | Uklonskovite | NaMg(SO4)F · 2H2O |
| 7.DF.10 | Kainite | KMg(SO4)Cl · 3H2O |
| 7.DF.10 | Kaliochalcite | KCu2(SO4)2[(OH)(H2O)] |
| 7.DF.15 | Natrochalcite | NaCu2(SO4)2(OH) · 2H2O |
| 7.DF.17 | Genplesite | Ca3Sn(SO4)2(OH)6 · 3H2O |
| 7.DF.17 | 'Unnamed (Ba-Sb Silicate-Sulphate-Hydroxide-Hydrate)' | Ba3Sb5+[(Si,S)O3(OH)]2(OH,O)6 · 3H2O |
| 7.DF.20 | Sideronatrite | Na2Fe(SO4)2(OH) · 3H2O |
| 7.DF.20 | Metasideronatrite | Na2Fe(SO4)2(OH) · H2O |
| 7.DF.25 | Fleischerite | Pb3Ge(SO4)2(OH)6 · 3H2O |
| 7.DF.25 | Mallestigite | Pb3Sb5+(SO4)(AsO4)(OH)6 · 3H2O |
| 7.DF.25 | Schaurteite | Ca3Ge(SO4)2(OH)6 · 4H2O |
| 7.DF.25 | Despujolsite | Ca3Mn4+(SO4)2(OH)6 · 3H2O |
| 7.DF.30 | Slavíkite | (H3O+)3Mg6Fe15(SO4)21(OH)18 · 98H2O |
| 7.DF.35 | Metavoltine | K2Na6Fe2+Fe3+6O2(SO4)12 · 18H2O |
| 7.DF.40 | Lannonite | Mg2Ca4Al4(SO4)8F8 · 24H2O |
| 7.DF.40 | Vlodavetsite | AlCa2(SO4)2F2Cl · 4H2O |
| 7.DF.45 | Peretaite | Ca(SbO)4(SO4)2(OH)2 · 2H2O |
| 7.DF.50 | Gordaite | NaZn4(SO4)(OH)6Cl · 6H2O |
| 7.DF.50 | Calamaite | Na2TiO(SO4)2 · 2H2O |
| 7.DF.52 | Huizingite-(Al) | [(NH4)9(SO4)2][(Al,Fe3+)3(OH)2(H2O)4(SO4)6] |
| 7.DF.55 | Clairite | (NH4)2Fe3(SO4)4(OH)3 · 3H2O |
| 7.DF.55 | Giacovazzoite | K5Fe3+3O(SO4)6 · 10H2O |
| 7.DF.57 | Magnanelliite | K3Fe3+2(SO4)4(OH)(H2O)2 |
| 7.DF.60 | Arzrunite | Cu4Pb2(SO4)(OH)4Cl6 · 2H2O (?) |
| 7.DF.60 | Evdokimovite | Tl4(VO)3(SO4)5(H2O)5 |
| 7.DF.62 | Bridgesite-(Ce) | CaCe2Cu6(SO4)4(OH)12 · 8H2O |
| 7.DF.65 | Elyite | Pb4Cu(SO4)O2(OH)4 · H2O |
| 7.DF.70 | Yecoraite | Fe3+3Bi5(Te6+O4)2(Te4+O3)O9 · 9H2O |
| 7.DF.70 | Lautenthalite | PbCu4(SO4)2(OH)6 · 3H2O |
| 7.DF.75 | Riomarinaite | Bi(SO4)(OH) · H2O |
| 7.DF.80 | Dukeite | Bi3+24Cr6+8O57(OH)6 · 3H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 14.7385% | 4,569 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Fluorescence of Scordariite
None
Other Information
Notes:
Readily soluble in water at room temperature
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Scordariite
mindat.org URL:
https://www.mindat.org/min-53674.html
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References for Scordariite
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2019) CNMNC Newsletter No 50, New minerals and nomenclature modifications approved in 2019. Mineralogical Magazine, 83 (4) 615-620 doi:10.1180/mgm.2019.46
Localities for Scordariite
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and 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).
All localities listed without proper references should be considered as questionable.
Italy (TL) | |
| Miyawaki et al. (2019) +2 other references |
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Monte Arsiccio Mine, Sant'Anna di Stazzema, Stazzema, Lucca Province, Tuscany, Italy