Derbylite Mineral Data

Derbylite Mineral Data +

General Derbylite Information

Chemical Formula:

(Fe+++,Fe++,Ti)7Sb+++O13(OH)

Composition:

Molecular Weight = 721.74 gm

Titanium 13.27 % Ti 22.13 % TiO₂

Iron 38.69 % Fe 19.91 % FeO / 33.19 % Fe₂O₃

Antimony 16.87 % Sb 20.19 % Sb₂O₃

Hydrogen 0.14 % H 1.25 % H₂O

Oxygen 31.03 % O

______ ______

100.00 % 96.67 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₃Fe²⁺₂Ti₂SbO₁₃(OH)

Environment:

In cinnaber-bearing placer gravels.

IMA Status:

Valid Species (Pre-IMA) 1897

Locality:

Tripuhy, Ouro Preto, Minas Gerais, Brazil. Link to MinDat.org Location Data.

Name Origin:

Named after the American Geologist Orville A. Derby 1851 - 1915 founder of the Brazilian Geological Survey.

Synonym:

ICSD 9825

PDF 35-599

Derbylite Image

Images:

Derbylite

Comments: Small black crystals of derbylite in matrix.
Location: Buca della Vena Mine, Stazzema (Ponte Stazzemese), Versilia, Apuan Alps, Lucca Province, Tuscany, Italy. Scale: Picture size 1.2 mm.
© Thomas Witzke / Abraxas-Verlag

Derbylite Crystallography

Axial Ratios:

a:b:c =0.499:1:0.3464

Cell Dimensions:

a = 7.16, b = 14.347, c = 4.97, Z = 2; beta = 104.61° V = 494.03 Den(Calc)= 4.85

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.853(1), 2.674(0.73), 3.186(0.43),

Crystal Structure:

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Moore P B , Araki T , Neues Jahrbuch fur Mineralogie, Abhandlungen , 126 (1976) p.292-303, Derbylite, Fe3+4Ti4+3Sb3+O13(OH), a novel close-packed oxide structure, Locality: Ouro Preto, Minas Gerias, Brazil

Physical Properties of Derbylite

Cleavage:

None

Color:

Pitch black, Black, Dark brown.

Density:

4.5 - 4.6, Average = 4.55

Diaphaniety:

Opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

5 - Apatite

Luster:

Resinous - Metallic

Streak:

brownish black

Optical Properties of Derbylite

Optical Data:

Biaxial (+), a=2.45, b=2.45, g=2.51, bire=0.0600, 2V(Calc)=0, 2V(Meas)=~0.

RL Color:

Gray with bluish green internal reflections.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Derbylite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	22.10	23.60
420 nm	21.30	22.80
440 nm	20.50	22.00
460 nm	19.80	21.20
480 nm	19.20	20.40
500 nm	18.80	19.90
520 nm	18.40	19.60
540 nm	18.10	19.30
560 nm	17.80	19.00
580 nm	17.60	18.70
600 nm	17.40	18.50
620 nm	17.30	18.40
640 nm	17.10	18.20
660 nm	16.90	18.00
680 nm	16.80	17.80
700 nm	16.70	17.70

**Calculated Relative Intensity Colors of Derbylite in Air**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	450%	500%
R₁
R₂

Calculated Properties of Derbylite

Electron Density:

r_electron=4.54 gm/cc
note: r_Derbylite=4.85 gm/cc.

Fermion Index

Fermion Index = 0.0255
Boson Index = 0.9745

Photoelectric:

PE_Derbylite= 67.25 barns/electron
U=PE_Derbylite x r_electron= 305.47 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Derbylite is Not Radioactive

Derbylite Classification

Dana Class:

46.2.3.2 (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites

(46.2)with miscellaneous formulae

(46.2.3)Derbylite Group

46.2.3.1 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m

46.2.3.2 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 2₁/m 2/m

46.2.3.3 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m

Strunz Class:

IV/C.23-30 IV - Oxides

IV/C - Oxides with metal : oxygen = 2:3 (M2O3 and related compounds)

IV/C.23 - Hemloite - Derbylite series

IV/C.23-10 Hemloite (As,Sb)2(Ti,V,Fe,Al)12O23OH P1 1

IV/C.23-15 Graeserite! (Fe,Ti)4Ti3AsO13(OH) A2/m 2/m

IV/C.23-20 Tomichite (V,Fe)4Ti3AsO13(OH) A2/m 2/m

IV/C.23-30 Derbylite (Fe,Fe,Ti)7SbO13(OH) P 2₁/m 2/m

Other Derbylite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Derbylite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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Derbylite

(Fe+++,Fe++,Ti)7Sb+++O13(OH)
Dana No: 46.2.3.2 Strunz No: IV/C.23-30
Locality:

Notes: