Henmilite
A valid IMA mineral species
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About Henmilite
Image of Prof. Henmi and his daughter, Dr. Henmi
Formula:
Ca2Cu[B(OH)4]2(OH)4
Colour:
Blue-violet
Lustre:
Vitreous
Hardness:
1½ - 2
Specific Gravity:
2.51
Crystal System:
Triclinic
Name:
Named for Professor Kitinosuke Henmi (逸見 吉之助) (28 June 1919, Okayama City, Japan - 11 November 1997) and his daughter Dr. Chiyoko Henmi (逸見 千代子) (1949 – 2018), Department of Earth Science, Okayama University, in recognition of their work on skarn minerals from Fuka. The mineral chiyokoite is also named after Chiyoko Henmi.
A synthetic Sr analogue is known.
Unique Identifiers
Mindat ID:
1866
Long-form identifier:
mindat:1:1:1866:7
IMA Classification of Henmilite
Approved
IMA Formula:
Ca2Cu2+[B(OH)4]2(OH)4
Approval year:
1981
First published:
1986
Classification of Henmilite
6.AC.30
6 : BORATES
A : Monoborates
C : B(O,OH)4, without and with additional anions; 1(T), 1(T)+OH, etc
6 : BORATES
A : Monoborates
C : B(O,OH)4, without and with additional anions; 1(T), 1(T)+OH, etc
26.1.5.1
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
1 : Monoborates
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
1 : Monoborates
9.3.25
9 : Borates
3 : Borates of Ca and Sr
9 : Borates
3 : Borates of Ca and Sr
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 |
|---|---|---|
| Hen | 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 Henmilite
Vitreous
Transparency:
Transparent
Colour:
Blue-violet
Streak:
Very pale violet to nearly white
Hardness:
1½ - 2 on Mohs scale
Comment:
Lower than pentahydroborite
Tenacity:
Fragile
Density:
2.51 g/cm3 (Measured) 2.523 g/cm3 (Calculated)
Optical Data of Henmilite
Type:
Biaxial (-)
RI values:
nα = 1.585(2) nβ = 1.608 nγ = 1.615(2)
2V:
Measured: 58° , Calculated: 56°
Max. Birefringence:
δ = 0.030
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:
Moderate (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
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
small
Pleochroism:
Strong
Comments:
X = pale pink, Y = pale purple, and Z = very pale blue
Comments:
Inclined extinction
Chemistry of Henmilite
Mindat Formula:
Ca2Cu[B(OH)4]2(OH)4
Element Weights:
Crystallography of Henmilite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 5.7617(5) Å, b = 7.9774(6) Å, c = 5.6488(4) Å
α = 109.611(6)°, β = 91.473(7)°, γ = 83.686(7)°
α = 109.611(6)°, β = 91.473(7)°, γ = 83.686(7)°
Ratio:
a:b:c = 0.722 : 1 : 0.708
Unit Cell V:
243.08 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Well developed {100} and {010} pinacoids
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
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Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
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2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
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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) |
|---|---|---|---|---|---|---|---|
| 0001050 | Henmilite | Nakai I, Okada H, Masutomi K, Koyama E, Nagashima K (1986) Henmilite, Ca2Cu(OH)4[B(OH)4]2, a new mineral from Fuka, Okayama Prefecture, Japan. II. Crystal structure American Mineralogist 71 1236-1239 | 1986 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.25 Å | (vs) |
| 4.35 Å | (s) |
| 3.709 Å | (s) |
| 3.302 Å | (s) |
| 2.494 Å | (sb) |
| 2.427 Å | (sb) |
| 2.346 Å | (s) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Type Occurrence of Henmilite
General Appearance of Type Material:
Anhedral masses and rarely as euhedral crystals up to 0.2 mm growing on the surface of, and within, pentahydroborite.
Place of Conservation of Type Material:
Department of Geology, National Science Museum, Tokyo.
Geological Setting of Type Material:
In pentahydroborite veins at a deposit of marble and contact-metamorphosed limestone / skarn.
Associated Minerals at Type Locality:
Synonyms of Henmilite
Other Language Names for Henmilite
Common Associates
Associations Based on Photo Data:
| 58 photos of Henmilite associated with Olshanskyite | Ca2[B3O3(OH)6](OH) · 3H2O |
| 17 photos of Henmilite associated with Calcite | CaCO3 |
| 6 photos of Henmilite associated with Chiyokoite | Ca3Si(CO3)[B(OH)4]O (OH)5 · 12H2O |
| 4 photos of Henmilite associated with Pentahydroborite | CaB2O(OH)6 · 2H2O |
| 3 photos of Henmilite associated with Shimazakiite | Ca2B2-xO5-3x(OH)3x (x = 0~0.06) |
| 1 photo of Henmilite associated with Aragonite | CaCO3 |
| 1 photo of Henmilite associated with Buryatite | Ca3(Si,Fe3+,Al)(SO4)B(OH)4(OH,O)6 · 12H2O |
| 1 photo of Henmilite associated with Cuspidine | Ca8(Si2O7)2F4 |
| 1 photo of Henmilite associated with Charlesite | Ca6(Al,Si)2(SO4)2[B(OH)4](OH,O)12 · 26H2O |
Related Minerals - Strunz-mindat Grouping
| 6.AC.05 | Sinhalite | MgAl(BO4) |
| 6.AC.10 | Pseudosinhalite | Mg2Al3(BO3)2(OH)O3 |
| 6.AC.15 | Béhierite | Ta(BO4) |
| 6.AC.15 | Schiavinatoite | Nb(BO4) |
| 6.AC.20 | Frolovite | Ca[B(OH)4]2 |
| 6.AC.25 | Hexahydroborite | Ca[B(OH)4]2 · 2H2O or CaB2O4 · 6H2O |
| 6.AC.35 | Bandylite | Cu[B(OH)4]Cl |
| 6.AC.40 | Teepleite | Na2[B(OH)4]Cl |
| 6.AC.45 | Moydite-(Y) | Y[B(OH)4](CO3) |
| 6.AC.50 | Carboborite | Ca2Mg[B(OH)4]2(CO3)2 · 4H2O |
| 6.AC.55 | Sulfoborite | Mg3[B(OH)4]2(SO4)(OH,F)2 |
| 6.AC.60 | Lüneburgite | Mg3[B2(OH)6](PO4)2 · 6H2O |
| 6.AC.65 | Seamanite | Mn2+3[B(OH)4](PO4)(OH)2 |
| 6.AC.70 | Cahnite | Ca2[B(OH)4](AsO4) |
Other Information
Notes:
Easily soluble in (1:2) HCl and (1:2) HNO3
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 Henmilite
mindat.org URL:
https://www.mindat.org/min-1866.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Henmilite
Reference List:
Nakai, I., Okada, H., Masutomi, K., Koyama, E., Nagashima, K. (1986) Henmilite, Ca2Cu(OH)4[B(OH)4]2, a new mineral from Fuka, Okayama Prefecture, Japan. American Mineralogist, 71 (9-10) 1234-1239
Frost, Ray L., Xi, Yunfei (2013) Vibrational spectroscopy of the borate mineral henmilite Ca2Cu[B(OH)4]2(OH)4. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 103. 356-360 doi:10.1016/j.saa.2012.11.009
Localities for Henmilite
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.
Japan (TL) | |
| Nakai et al. (1986) +2 other references |
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Fuka mine, Fuka, Bitchū, Takahashi City, Okayama Prefecture, Japan