Derbylite
A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
About Derbylite
Orville Adelbert Derby
Formula:
Fe3+4Ti3Sb3+O13(OH)
also given as Fe2+xFe3+4-2xTi4+3+xSb3+O13(OH)
Colour:
Pitch-black, dark brown (when translucent)
Lustre:
Sub-Adamantine, Resinous, Metallic
Hardness:
5
Specific Gravity:
4.53 - 4.62
Crystal System:
Monoclinic
Name:
After American geologist Orville Adelbert Derby [July 23, 1851 Kellogsville, New York - November 27, 1915 Rio de Janeiro, Brazil), former Director, Brazilian Geological Survey.
Type Locality:
Homeotypic with graeserite, its As analogue. Both crystallize in the same point group, but different space group.
Also the Fe-Sb analogue of tomichite.
Compare batisivite.
Also the Fe-Sb analogue of tomichite.
Compare batisivite.
Unique Identifiers
Mindat ID:
1263
Long-form identifier:
mindat:1:1:1263:4
IMA Classification of Derbylite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Fe3+4Ti4+3Sb3+O13(OH)
First published:
1897
Classification of Derbylite
4.JB.55
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
B : Arsenites, antimonites, bismuthites; with additional anions, without H2O
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
B : Arsenites, antimonites, bismuthites; with additional anions, without H2O
46.2.3.2
46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
24.3.2
24 : Antimonates and Antimonites
3 : Antimonates of Ti and Pb
24 : Antimonates and Antimonites
3 : Antimonates of Ti and Pb
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 |
|---|---|---|
| Dby | 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 Derbylite
Sub-Adamantine, Resinous, Metallic
Transparency:
Opaque
Colour:
Pitch-black, dark brown (when translucent)
Streak:
Brown
Hardness:
5 on Mohs scale
Hardness:
VHN100=1033 - 1121 kg/mm2 - Vickers
Tenacity:
Very brittle
Cleavage:
None Observed
Fracture:
Conchoidal, Sub-Conchoidal
Density:
4.53 - 4.62 g/cm3 (Measured) 4.76 g/cm3 (Calculated)
Optical Data of Derbylite
Type:
Biaxial (+)
RI values:
nα = 2.45 nβ = 2.45 nγ = 2.51
Birefringence:
0.06
Max. Birefringence:
δ = 0.060
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
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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Optical Extinction:
X = a; Y = b; Z = c.
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 400nm | 22.1% | 23.6% |
| 420nm | 21.3% | 22.8% |
| 440nm | 20.5% | 22.0% |
| 460nm | 19.8% | 21.2% |
| 480nm | 19.2% | 20.4% |
| 500nm | 18.8% | 19.9% |
| 520nm | 18.4% | 19.6% |
| 540nm | 18.1% | 19.3% |
| 560nm | 17.8% | 19.0% |
| 580nm | 17.6% | 18.7% |
| 600nm | 17.4% | 18.5% |
| 620nm | 17.3% | 18.4% |
| 640nm | 17.1% | 18.2% |
| 660nm | 16.9% | 18.0% |
| 680nm | 16.8% | 17.8% |
| 700nm | 16.7% | 17.7% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 23.6%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Gray
Internal Reflections:
Bluish green
Pleochroism:
Non-pleochroic
Chemistry of Derbylite
Mindat Formula:
Fe3+4Ti3Sb3+O13(OH)
also given as Fe2+xFe3+4-2xTi4+3+xSb3+O13(OH)
also given as Fe2+xFe3+4-2xTi4+3+xSb3+O13(OH)
Element Weights:
Crystallography of Derbylite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Cell Parameters:
a = 7.156 Å, b = 14.347 Å, c = 4.97 Å
β = 104.69°
β = 104.69°
Ratio:
a:b:c = 0.499 : 1 : 0.346
Unit Cell V:
493.58 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals prismatic, elongated [001], exhibiting numerous forms, mostly {hk0}; small grains.
Twinning:
On {011} or {153}. Commonly as cruciform twins crossing at 57°38½', and rarely as trillings.
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
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
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
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0014704 | Derbylite | Moore P B, Araki T (1976) Derbylite, Fe3+4Ti4+3Sb3+O13(OH), a novel close-packed oxide structure Neues Jahrbuch fur Mineralogie, Abhandlungen 126 292-303 | 1976 | Ouro Preto, Minas Gerias, Brazil | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.00 Å | (20) |
| 3.83 Å | (20) |
| 3.19 Å | (50) |
| 3.12 Å | (40) |
| 2.85 Å | (100) |
| 2.67 Å | (80) |
| 2.48 Å | (30) |
| 2.39 Å | (30) |
Comments:
35-599
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 57 : Other minerals formed by human processes |
Type Occurrence of Derbylite
General Appearance of Type Material:
Small grains and complex prismatic crystals.
Place of Conservation of Type Material:
The Natural History Museum, London, England, UK: #80143.
Geological Setting of Type Material:
Cinnabar-bearing placer gravels.
Associated Minerals at Type Locality:
Other Language Names for Derbylite
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 4.JB. | Cuyaite | Ca2Mn3+As3+14O24Cl |
| 4.JB. | Brattforsite | Mn19(AsO 3)12Cl2 |
| 4.JB.05 | Fetiasite | (Fe3+,Fe2+,Ti)3(As2O5)O2 |
| 4.JB.10 | Manganarsite | Mn3(As2O4)(OH)4 |
| 4.JB.15 | 'UM1984-09-AsO:ClHMn' | Mn10As6O18(OH)Cl |
| 4.JB.15 | Magnussonite | Mn2+10(As3+O3)6(OH,Cl)2 |
| 4.JB.20 | Armangite | Mn2+26(AsO3)14(HAsO3)4(CO3) |
| 4.JB.25 | Nanlingite | Na(Ca5Li)Mg12(AsO3)2[Fe(AsO3)6]F14 |
| 4.JB.30 | Asbecasite | Ca3(Ti,Sn4+)Be2(AsO3)6(SiO4)2 |
| 4.JB.35 | Stenhuggarite | CaFeSb(AsO3)2O |
| 4.JB.40 | Trigonite | Pb3Mn2+(AsO3)2(HAsO3) |
| 4.JB.45 | Finnemanite | Pb5(AsO3)3Cl |
| 4.JB.50 | Gebhardite | Pb8(As2O5)2OCl6 |
| 4.JB.55 | Graeserite | Fe3+4Ti3As3+O13(OH) |
| 4.JB.55 | Tomichite | (V,Fe)4Ti3AsO13(OH) |
| 4.JB.60 | Hemloite | (Ti,V3+,Fe3+,Al)12(As3+,Sb3+)2O23(OH) |
| 4.JB.65 | Freedite | Cu+Pb8(AsO3)2O3Cl5 |
| 4.JB.70 | Georgiadesite | Pb4(As3+O3)Cl4(OH) |
| 4.JB.75 | Szklaryite | ◻Al6BAs3+3O15 |
| 4.JB.75 | Ekatite | (Fe3+,Fe2+,Zn)12(AsO3)6(AsO3,HSiO4)2(OH)6 |
| 4.JB.85 | Lepageite | Mn2+3(Fe3+7Fe2+4)O3[Sb3+5As3+8O34] |
| 4.JB.90 | Bianchiniite | Ba2(TiV)(As2O5)2OF |
Fluorescence of Derbylite
Not fluorescent
Other Information
Notes:
Not soluble in acids. Decomposed by fusion in KHSO4.
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 Derbylite
mindat.org URL:
https://www.mindat.org/min-1263.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Derbylite
Reference List:
Hussak, E., Prior, G. T. (1897) On Derbylite, a New Antimono-titanate of Iron, from Tripuhy, Brazil. Mineralogical Magazine and Journal of the Mineralogical Society, 11 (52) 176-179 doi:10.1180/minmag.1897.011.52.03
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.67
Mellini,, M., Orlandi, P., Perchiazzi, N. (1983) Derbylite from Buca della Vena mine, Apuane Alps, Italy. The Canadian Mineralogist, 21 (3) 513-516
Mellini, M., Orlandi, P., Vezzalini, G. (1986) V-bearing derbylite from the Buca della Vena mine, Apuan Alps, Italy. Mineralogical Magazine, 50 (356) 328-331 doi:10.1180/minmag.1986.050.356.22
Localities for Derbylite
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.
Brazil (TL) | |
| Mineralogical Magazine (1895) +3 other references |
| Brugger et al. (1997) | |
Italy | |
| Mellini et al. (1986) |
| Biagioni et al. (2013) +1 other reference |
Quick NavTopAbout DerbyliteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Buca della Vena Mine, Pontestazzemese, Stazzema, Lucca Province, Tuscany, Italy