Shagamite
A valid IMA mineral species
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About Shagamite
Formula:
KFe11O17
Colour:
dark brown
Lustre:
Sub-Metallic
Hardness:
5
Specific Gravity:
4.12 (Calculated)
Crystal System:
Hexagonal
Name:
Shagamite is named in honor of Dr. Reginald Shagam (1926–2008). He was one of the founders of the Department of Geology at Ben-Gurion University of the Negev in Israel. His geological works in the Andes made him famous, earning him the nickname “El Tigre De Los Andes”.
Type Locality:
Isostructural with:
The Fe3+-analogue of kahlenbergite. Chemically similar to jeppeite. Also compare priderite and 'K-ferrite'.
Unique Identifiers
Mindat ID:
55382
Long-form identifier:
mindat:1:1:55382:7
IMA Classification of Shagamite
Approved
IMA Formula:
KFe3+11O17
Approval year:
2021
Approval history:
IMA No. 2020-091
Classification of Shagamite
4.CC.
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
C : With large and medium-sized cations
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
C : 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 |
|---|---|---|
| Sgm | 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 Shagamite
Sub-Metallic
Transparency:
Opaque
Colour:
Dark brown
Comment:
In thin plates, the mineral is translucent and varies in color from brown to light brown depending on thickness. Locally, the cleavage surface is light brown with a golden hue and exhibits a pearly luster, possibly reflecting surface hydration.
Hardness:
5 on Mohs scale
Hardness:
VHN25=507 kg/mm2 - Vickers
Cleavage:
Perfect
present along (001), accompanied by prominent fracturing parallel to this plane.
present along (001), accompanied by prominent fracturing parallel to this plane.
Fracture:
Conchoidal, Step-Like
Comment:
Fracture is conchoidal at angles to (001) and stepped parallel on (001).
Density:
4.12 g/cm3 (Calculated)
Optical Data of Shagamite
Anisotropism:
strong
Bireflectance:
weak
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 470nm | 17.8% | 22.1% |
| 546nm | 16.5% | 21.3% |
| 589nm | 15.8% | 20.2% |
| 650nm | 12.3% | 17.8% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 22.1%.
R1 shown in black, R2 shown in red
Colour in reflected light:
gray
Internal Reflections:
Brown-orange
Pleochroism:
Strong
Comments:
dark gray perpendicular to the c-axis to light gray parallel to the c-axis
Chemistry of Shagamite
Mindat Formula:
KFe11O17
Elements listed:
Crystallography of Shagamite
Crystal System:
Hexagonal
Class (H-M):
6/mmm(6/m2/m2/m) - Dihexagonal Dipyramidal
Space Group:
P63/mmc
Setting:
P63/mmc
Cell Parameters:
a = 5.9327(5) Å, c = 23.782(3) Å
Ratio:
a:c = 1 : 4.009
Unit Cell V:
724.91 ų (Calculated from Unit Cell)
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.89 Å | (100) |
| 5.945 Å | (29) |
| 2.834 Å | (61) |
| 2.654 Å | (39) |
| 2.554 Å | (25) |
| 2.444 Å | (23) |
| 2.375 Å | (22) |
| 1.483 Å | (29) |
Type Occurrence of Shagamite
General Appearance of Type Material:
Shagamite forms platy crystals flattened on the (001). Individual crystals reach lengths of up to 0.5 mm and are typically no more than 0.15 mm thick. Most crystals contain inclusions of other ferrites.
Place of Conservation of Type Material:
Collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5634/1
Geological Setting of Type Material:
ferrite zone of gehlenite hornfels from the Hatrurim Complex exposed near Mt. Ye’elim, Hatrurim Basin, Israel. The mineral occurs in outer zones of gehlenite rock blocks that were heterogeneously altered by high-temperature (>1200 °C) ferritization. Ferritization was induced by K-bearing fluids or melts, generated as a by-product of late combustion processes.
Associated Minerals at Type Locality:
Synonyms of Shagamite
Other Language Names for Shagamite
Related Minerals - Strunz-mindat Grouping
| 4.CC. | Xuite | Ca3Fe3+2[(AlO3(OH)]3 |
| 4.CC. | Yttriaite-(Y) | Y2O3 |
| 4.CC. | Allendeite | Sc4Zr3O12 |
| 4.CC. | Chlorkyuygenite | Ca12Al14O32[(H2O)4Cl2] |
| 4.CC. | Oboniobite | Mg4Nb2O9 |
| 4.CC. | Botuobinskite | SrFe2+Mg2(Cr3+6Ti4+12)[O36(OH)2] |
| 4.CC. | Mirnyite | SrZr4+Mg2(Cr3+6Ti4+12)O38 |
| 4.CC. | Haitaite-(La) | LaU4+Fe3+2(Ti13Fe2+4Fe3+)O38 |
| 4.CC. | Bitikleite | Ca3(Sb5+Sn4+)[AlO4]3 |
| 4.CC. | Anzaite-(Ce) | Ce3+ 4Fe2+Ti6O18 (OH)2 |
| 4.CC. | Heamanite-(Ce) | (K0.5Ce0.5)TiO3 |
| 4.CC. | Priscillagrewite-(Y) | (Ca2Y)Zr2(AlO4)3 |
| 4.CC. | Strandite | Pb3Mn3+4Mn4+3O15 |
| 4.CC. | Saranovskite | SrCaFe2+2(Cr4Ti2)Ti12O38 |
| 4.CC.05 | Chrombismite | Bi3+16Cr6+O27 |
| 4.CC.10 | Freudenbergite | Na2(Ti,Fe)8O16 |
| 4.CC.10 | Fluormayenite | Ca12Al14O32F2 |
| 4.CC.10 | Fluorkyuygenite | Ca12Al14O32[(H2O)4F2] |
| 4.CC.15 | Grossite | CaAl4O7 |
| 4.CC.17 | Goldschmidtite | KNbO3 |
| 4.CC.20 | 'Unnamed (HBU UK-4)' | NaFe2+Zn2(Ti,Fe3+,Nb)6Ti12O38 |
| 4.CC.20 | Chlormayenite | Ca12Al14O32[◻4Cl2] |
| 4.CC.20 | Paseroite | PbMn2+(Mn2+,Fe3+)2(V5+,Ti,◻)18O38 |
| 4.CC.20 | Mianningite | (◻,Pb,Ce,Na)(U4+,Mn,U6+)Fe3+2 (Ti,Fe3+)18O38 |
| 4.CC.20 | 'UM1987-03-O:FePbTiU' | ~(U,Pb)(Ti,Fe3+,Fe2+,Mn)21O38 |
| 4.CC.22 | Gorerite | CaAlFe3+11O19 |
| 4.CC.22 | Kahlenbergite | KAl11O17 |
| 4.CC.25 | Hopmannite | Ba2(Ti5Fe)O13 |
| 4.CC.25 | Nixonite | Na2Ti6O13 |
| 4.CC.25 | Yafsoanite | Ca3Te6+2(ZnO4)3 |
| 4.CC.30 | Latrappite | Ca2NbFe3+O6 |
| 4.CC.30 | Natroniobite | NaNbO3 |
| 4.CC.30 | Perovskite | CaTiO3 |
| 4.CC.30 | Lueshite | NaNbO3 |
| 4.CC.30 | Bariolakargiite | BaZrO3 |
| 4.CC.30 | Barioperovskite | BaTiO3 |
| 4.CC.30 | Megawite | CaSnO3 |
| 4.CC.30 | Lakargiite | Ca(Zr,Sn,Ti)O3 |
| 4.CC.32 | Usturite | Ca3(Sb5+Zr)[Fe3+O4]3 |
| 4.CC.32 | Elbrusite | Ca3(U6+0.5Zr1.5)[Fe3+O4]3 |
| 4.CC.32 | Monteneveite | Ca3Sb5+2(Fe3+2Fe2+)O12 |
| 4.CC.32 | Dzhuluite | Ca3(Sb5+Sn4+)[Fe3+O4]3 |
| 4.CC.35 | Tausonite | SrTiO3 |
| 4.CC.35 | Loparite | (Na,REE)2Ti2O6 |
| 4.CC.35 | Panguite | (Ti,Al,Sc,Mg,Zr,Ca)1.8O3 |
| 4.CC.35 | Isolueshite | (Na,La)NbO3 |
| 4.CC.35 | Macedonite | PbTiO3 |
| 4.CC.37 | Pauloabibite | NaNbO3 |
| 4.CC.40 | Landauite | NaMnZn2(Ti,Fe)6Ti12O38 |
| 4.CC.40 | Mathiasite | (Mg,Cr,Fe,Ca,K)2(Ti,Zr,Cr,Fe)5O12 |
| 4.CC.40 | Senaite | Pb(Mn,Y,U)(Fe,Zn)2(Ti,Fe,Cr,V)18(O,OH)38 |
| 4.CC.40 | Gramaccioliite-(Y) | (Pb,Sr)(Y,Mn)Fe3+2(Ti,Fe3+)18O38 |
| 4.CC.40 | Lindsleyite | (Ba,Sr)(Zr,Ca)(Fe,Mg)2(Ti,Cr,Fe)18O38 |
| 4.CC.40 | Crichtonite | Sr(Mn,Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH)38 |
| 4.CC.40 | Loveringite | (Ca,Ce,La)(Zr,Fe)(Mg,Fe)2(Ti,Fe,Cr,Al)18O38 |
| 4.CC.40 | Cleusonite | (Pb,Sr)(U4+,U6+)(Fe2+,Zn)2(Ti,Fe2+,Fe3+)18(O,OH)38 |
| 4.CC.40 | Davidite-(Ce) | Ce(Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH,F)38 |
| 4.CC.40 | Davidite-(La) | La(Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH,F)38 |
| 4.CC.40 | 'Davidite-(Y)' | (La,Ce,Na,Ca,Pb)(Y,Fe2+,◻)(Fe2+,Mn2+)2(Ti,Fe3+,Nb,Zr)18O38 (hypothetical) |
| 4.CC.40 | 'Uhligite' | Ca3(Ti,Al,Zr)9O20 ? |
| 4.CC.40 | Dessauite-(Y) | (Sr,Pb)(Y,U)(Ti,Fe3+)20O38 |
| 4.CC.45 | Diaoyudaoite | NaAl11O17 |
| 4.CC.45 | Yimengite | K(Cr,Ti,Fe,Mg)12O19 |
| 4.CC.45 | Nežilovite | PbZn2Mn4+2Fe3+8O19 |
| 4.CC.45 | Hawthorneite | BaMgTi3Cr4Fe2+2Fe3+2O19 |
| 4.CC.45 | Mizraite-(Ce) | Ce(Al11Mg)O19 |
| 4.CC.45 | Haggertyite | BaFe2+4Fe3+2Ti5MgO19 |
| 4.CC.45 | Lindqvistite | Pb2Mn2+Fe16O27 |
| 4.CC.45 | Hibonite | CaAl12O19 |
| 4.CC.45 | Kangite | (Sc,Ti,Al,Zr,Mg,Ca,◻)2O3 |
| 4.CC.45 | Chihuahuaite | FeAl12O19 |
| 4.CC.45 | Barioferrite | BaFe3+12O19 |
| 4.CC.45 | Plumboferrite | Pb[Fe3+10.67Mn2+0.33Pb]O18.33 |
| 4.CC.45 | Batiferrite | BaTi2Fe3+8Fe2+2O19 |
| 4.CC.45 | Magnetoplumbite | PbFe3+12O19 |
| 4.CC.50 | Jeppeite | K2Ti6O13 |
| 4.CC.55 | Zenzénite | Pb3Fe3+4Mn4+3O15 |
| 4.CC.60 | 'Mengxianminite (of Huang et al.)' | (Ca,Na)3(Fe,Mn)2Mg2(Sn,Zn)5Al8O29 |
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) | 4.2251% | 1,310 | 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
Other Information
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 Shagamite
mindat.org URL:
https://www.mindat.org/min-55382.html
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References for Shagamite
Localities for Shagamite
Showing 1 localities.
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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.
Israel (TL) | |
| Miyawaki et al. (2021) +1 other reference |
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Ye’elim Mount, Tamar Regional Council, Beersheba Subdistrict, Southern District, Israel