Delafossite Mineral Data

Delafossite Mineral Data +

General Delafossite Information

Chemical Formula:

Cu+Fe+++O2

Composition:

Molecular Weight = 151.39 gm

Iron 36.89 % Fe 52.74 % Fe₂O₃

Copper 41.97 % Cu 47.26 % Cu₂O

Oxygen 21.14 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CuFe³⁺O₂

Environment:

Principally as a secondary mineral near the base of the oxidized zone of copper deposits, less commonly a primary mineral.

IMA Status:

Valid Species (Pre-IMA) 1873

Locality:

Calumet and Arizona mine, Bisbee, Cochise Co., Arizona, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Gabrial Delafosse (1796-1878), French mineralogist and crystallographer.

Synonym:

ICSD 60844

PDF 39-246

Delafossite Image

Images:

Delafossite

Comments: Black crystals of delafossite on matrix.
Location: Clara Mine, Rankach valley, Oberwolfach, Wolfach, Black Forest, Baden-W?rttemberg, Germany. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Delafossite Crystallography

Axial Ratios:

a:c = 1:5.63157

Cell Dimensions:

a = 3.04, c = 17.12, Z = 3; V = 137.02 Den(Calc)= 5.50

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: R 3m

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

By Intensity(I/I_o): 2.508(1), 1.512(0.4), 2.86(0.35),

Crystal Structure:

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Pabst A , American Mineralogist , 23 (1938) p.175-176, Crystal structure and density of delafossite

View Additional jPOWD Structure files for Delafossite
[1]

Physical Properties of Delafossite

Cleavage:

[1010] Indistinct

Color:

Black.

Density:

5.41

Diaphaniety:

Opaque

Fracture:

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

Habit:

Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

5.5 - Knife Blade

Luminescence:

Non-fluorescent.

Luster:

Metallic

Magnetism:

Magnetic after heating

Streak:

black

Optical Properties of Delafossite

Dichroism (e):

light golden brown.

Dichroism (w):

rose brown.

Optical Data:

Uniaxial (?).

NCalc= 2.52 - from Gladstone-Dale relationship (KC = 0.2767) where Ncalc=Dcalc*KC+1
NCalc= 2.5 - from Gladstone-Dale relationship (KC = 0.2767) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Strong.

RL Color:

Brownish rose.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Delafossite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	18.40	22.20
420 nm	18.60	22.30
440 nm	18.80	22.40
460 nm	19.00	22.60
480 nm	19.00	22.90
500 nm	18.90	23.20
520 nm	19.00	23.40
540 nm	19.00	23.40
560 nm	19.10	23.20
580 nm	19.20	23.00
600 nm	19.30	23.00
620 nm	19.60	23.20
640 nm	20.00	23.50
660 nm	20.60	23.80
680 nm	21.10	24.20
700 nm	21.80	24.80

**Calculated Relative Intensity Colors of Delafossite in Air**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	450%	470%
R₁
R₂

Calculated Properties of Delafossite

Electron Density:

r_electron=5.16 gm/cc
note: r_Delafossite=5.50 gm/cc.

Fermion Index

Fermion Index = 0.00792
Boson Index = 0.99208

Photoelectric:

PE_Delafossite= 30.25 barns/electron
U=PE_Delafossite x r_electron= 156.03 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Delafossite is Not Radioactive

Delafossite Classification

Dana Class:

7.1.1.1 (7)Multiple Oxides

(7.1)where A B X2 containing copper

(7.1.1)Dana Group

7.1.1.1 Delafossite CuFeO2 R 3m 3 2/m

7.1.1.2 Mcconnellite CuCrO2 R 3m 3 2/m

Strunz Class:

IV/A.05-30 IV - Oxides

IV/A - Oxides with metal : oxygen = 1:1 and 2:1 (M2O,MO)

IV/A.05 - Periclase Group, Tenorite - Crednerite series

IV/A.05-10 Tenorite CuO C 2/c 2/m

IV/A.05-20 Paramelaconite Cu2Cu2O3 I 4₁/amd 4/m 2/m 2/m

IV/A.05-30 Delafossite CuFeO2 R 3m 3 2/m

IV/A.05-40 Mcconnellite CuCrO2 R 3m 3 2/m

IV/A.05-50 Crednerite CuMnO2 A2/m 2/m

Other Delafossite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)

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Print or Cut-and-Paste your Delafossite Specimen Label here :

Delafossite

Cu+Fe+++O2
Dana No: 7.1.1.1 Strunz No: IV/A.05-30
Locality:

Notes: