Ohmilite
A valid IMA mineral species
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About Ohmilite
Formula:
Sr3(Ti,Fe3+)(Si4O12)(O,OH) · 2-3H2O
Colour:
Pink to pinkish brown
Hardness:
3½
Specific Gravity:
3.38
Crystal System:
Monoclinic
Name:
Named in 1973 by Masayuki Komatsu, Kazuya Chihara, and Tadato Mizota after the type locality of Ohmi, Niigata Prefecture, Central Japan.
Type Locality:
Unique Identifiers
Mindat ID:
2963
Long-form identifier:
mindat:1:1:2963:2
Similar Names
| Homilite | A valid IMA mineral species - grandfathered | Ca2(Fe2+,Mg)B2Si2O10 |
IMA Classification of Ohmilite
Approved
IMA Formula:
Sr3(Ti4+,Fe3+)(Si2O6)2(O,OH)(H2O)2
Approval year:
1974
First published:
1973
Classification of Ohmilite
9.DH.10
9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
9 : SILICATES (Germanates)
D : Inosilicates
H : Inosilicates with 4-periodic single chains, Si4O12
65.3.4.3
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
3 : Single-Width Unbranched Chains, W=1 with chains P=4
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
3 : Single-Width Unbranched Chains, W=1 with chains P=4
14.9.7
14 : Silicates not Containing Aluminum
9 : Silicates of Ti
14 : Silicates not Containing Aluminum
9 : Silicates of Ti
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 |
|---|---|---|
| Oh | 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 Ohmilite
Transparency:
Translucent
Colour:
Pink to pinkish brown
Streak:
White
Hardness:
3½ on Mohs scale
Cleavage:
Perfect
Parallel to (100)
Parallel to (100)
Density:
3.38 g/cm3 (Measured) 3.394 g/cm3 (Calculated)
Optical Data of Ohmilite
Type:
Biaxial
RI values:
nα = 1.649 nγ = 1.715
Max. Birefringence:
δ = 0.066
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Dispersion:
r < v strong
Pleochroism:
Weak
Comments:
Very weak, colourless to light pink.
Chemistry of Ohmilite
Mindat Formula:
Sr3(Ti,Fe3+)(Si4O12)(O,OH) · 2-3H2O
Element Weights:
Crystallography of Ohmilite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P21/m
Cell Parameters:
a = 10.97 Å, b = 7.79 Å, c = 7.81 Å
β = 100.9°
β = 100.9°
Ratio:
a:b:c = 1.408 : 1 : 1.003
Unit Cell V:
655.37 ų (Calculated from Unit Cell)
Z:
2
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0014415 | Ohmilite | Mizota T, Komatsu M, Chihara K (1973) On the crystal structure of Sr3TiSi4O12(OH)*2H2O, a new mineral Mineralogical Journal 7 302-305 | 1973 | Ohmi District, Niigata Prefecture, Central Japan | 0 | 293 | |
| 0000908 | Ohmilite | Mizota T, Komatsu M, Chihara K (1983) A refinement of the crystal structure of ohmilite, Sr3(Ti,Fe3+)(O,OH)(Si2O6)2* 2-3H2O American Mineralogist 68 811-817 |  | 1983 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.83 Å | (70) |
| 5.39 Å | (77) |
| 4.62 Å | (100) |
| 3.83 Å | (90) |
| 3.471 Å | (42) |
| 3.409 Å | (40) |
| 3.264 Å | (85) |
| 3.037 Å | (80) |
| 2.831 Å | (54) |
| 2.730 Å | (57) |
| 2.600 Å | (90) |
| 2.564 Å | (40) |
| 2.400 Å | (42) |
| 2.101 Å | (42) |
| 2.076 Å | (42) |
| 2.028 Å | (42) |
Comments:
Ōmi, Niigata Prefecture, Japan. The data are from Komatsu et al. (1973).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Ohmilite
General Appearance of Type Material:
Aggregates of very fine-grained crystals or occasionally spherulitic aggregates of radially arranged crystals in interstitial parts of albite aggregates. To 0.2 mm.
Place of Conservation of Type Material:
Niigata University, Niigata, Japan (type).
Geological Setting of Type Material:
In an amphibole-quartz-albitite dike cutting serpentinite.
Associated Minerals at Type Locality:
Synonyms of Ohmilite
Other Language Names for Ohmilite
Common Associates
Associations Based on Photo Data:
| 16 photos of Ohmilite associated with Magnesio-riebeckite | ◻Na2(Mg3Fe3+2)(Si8O22)(OH)2 |
| 11 photos of Ohmilite associated with Strontio-orthojoaquinite | (Na,Fe)2Sr2Ba2Ti2[Si4O12]2O2(O,OH)2 · H2O |
| 7 photos of Ohmilite associated with Albite | Na(AlSi3O8) |
| 6 photos of Ohmilite associated with Benitoite | BaTi(Si3O9) |
Related Minerals - Strunz-mindat Grouping
| 9.DH. | Devilliersite | Ca4Ca2Fe3+10O4[(Fe3+10Si2)O36] |
| 9.DH. | 'Gageite-2M' | (Mn,Mg,Zn)42Si16O54(OH)40 |
| 9.DH. | Bavsiite | Ba2V2O2[Si4O12] |
| 9.DH. | Yuzuxiangite | Sr3Fe3+(Si2O6)2(OH) · 3H2O |
| 9.DH. | Louisfuchsite | Ca2(Mg4Ti2)(Al4Si2)O20 |
| 9.DH.05 | Leucophanite | NaCaBeSi2O6F |
| 9.DH.15 | Haradaite | SrVSi2O7 |
| 9.DH.15 | Suzukiite | BaVSi2O7 |
| 9.DH.20 | Shcherbakovite | (K,Ba)KNa(Ti,Nb)2(Si4O12)O2 |
| 9.DH.20 | Batisite | BaNaNaTi2(Si4O12)O2 |
| 9.DH.20 | Noonkanbahite | BaKNaTi2(Si4O12)O2 |
| 9.DH.25 | Taikanite | Sr3BaMn2+2(Si4O12)O2 |
| 9.DH.30 | Krauskopfite | BaSi2O5 · 3H2O |
| 9.DH.35 | Gageite | Mn21(Si4O12)2O3(OH)20 |
| 9.DH.35 | Balangeroite | (Mg,Fe2+,Fe3+,Mn2+)42Si16O54(OH)40 |
| 9.DH.40 | Kuratite | Ca2(Fe2+5Ti)O2[Si4Al2O18] |
| 9.DH.40 | Aenigmatite | Na4[Fe2+10Ti2]O4[Si12O36] |
| 9.DH.40 | Dorrite | Ca4(Mg3Fe3+9)O4(Si3Al8Fe3+O36) |
| 9.DH.40 | Serendibite | Ca4[Mg6Al6]O4[Si6B3Al3O36] |
| 9.DH.40 | Rhönite | Ca4[Mg8Fe3+2Ti2]O4[Si6Al6O36] |
| 9.DH.40 | Khesinite | Ca4(Mg3Fe3+9)O4(Fe3+9Si3)O36 |
| 9.DH.40 | 'UM1991-29-SiO:FeMgNa' | Na4(Mg5Fe3+7)O4[Si9Fe3+3O36] |
| 9.DH.40 | Høgtuvaite | Ca4[Fe2+6Fe3+6]O4[Si8Be2Al2O36] |
| 9.DH.40 | 'Leucorhönite' | Ca2(Mg,Fe3+,Al)6(Si,Al)6O20 |
| 9.DH.40 | Welshite | Ca4Mg9Sb3O4[Si6Be3AlFe2O36] |
| 9.DH.40 | Wilkinsonite | Na2Fe2+4Fe3+2(Si6O18)O2 |
| 9.DH.40 | Krinovite | Na2Mg4Cr3+2(Si6O18)O2 |
| 9.DH.40 | Makarochkinite | (Ca,Na)4[Fe2+8Fe3+2Ti2]O4[Si8Be2Al2O36] |
| 9.DH.45 | Sapphirine | Mg4(Mg3Al9)O4[Si3Al9O36] |
| 9.DH.50 | Khmaralite | (Mg,Al,Fe)16[(Al,Si,Be)12O36]O4 |
| 9.DH.55 | 'UM1988-26-SiO:AlMg' | Mg4Al2O[Si3Al2O15] |
| 9.DH.55 | Surinamite | (Mg,Fe)3Al4BeSi3O16 |
| 9.DH.60 | Deerite | Fe2+6Fe3+3(Si6O17)O3(OH)5 |
| 9.DH.65 | Taneyamalite | (Na,Ca)Mn2+12(Si,Al)12(O,OH)44 |
| 9.DH.65 | Howieite | Na(Fe2+,Fe3+,Al,Mg)12(Si6O17)2(O,OH)10 |
| 9.DH.70 | Johninnesite | Na2Mn2+9Mg7(OH)8[AsO4]2[Si6O17]2 |
| 9.DH.75 | Agrellite | NaCa2Si4O10F |
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 Ohmilite
mindat.org URL:
https://www.mindat.org/min-2963.html
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References for Ohmilite
Reference List:
Mizota, Tadato, Komatsu, Masayuki, Chihara, Kazuya (1973) On the crystal structure of Sr3TiSi4O12(OH)·2H2O, a new mineral. Mineralogical Journal, 7 (3) 302-305 doi:10.2465/minerj1953.7.302
Komatsu, Masayuki, Chihara, Kazuya, Mizota, Tadato (1973) A new strontium-titanium hydrous silicate mineral from Ohmi, Niigata Prefecture, central Japan. Mineralogical Journal, 7 (3) 298-301 doi:10.2465/minerj1953.7.298
Mizota, Tadato, Komatsu, Masayuki, Chihara, Kazuya (1973) On the crystal structure of Sr3TiSi4O12(OH)·2H2O, a new mineral. Mineralogical Journal, 7 (3) 302-305 doi:10.2465/minerj1953.7.302
Localities for Ohmilite
Showing 4 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.
Japan | |
| ... +1 other reference |
| Komatsu et al. (1973) | |
| Hiroaki Tano specimen +1 other reference |
| Hiroaki Tano's collection |
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Ōmi, Itoigawa City, Niigata Prefecture, Japan