Ishikawaite Mineral Data

Ishikawaite Mineral Data +

General Ishikawaite Information

Chemical Formula:

(U,Fe,Y,Ca)(Nb,Ta)O4 (?)

Composition:

Molecular Weight = 294.45 gm

Calcium 1.36 % Ca 1.90 % CaO

Yttrium 6.04 % Y 7.67 % Y₂O₃

Uranium 24.25 % U 27.51 % UO₂

Tantalum 15.36 % Ta 18.76 % Ta₂O₅

Niobium 23.66 % Nb 33.85 % Nb₂O₅

Iron 7.59 % Fe 9.76 % FeO

Oxygen 21.73 % O

______ ______

100.00 % 99.46 % = TOTAL OXIDE

Empirical Formula:

U_0.3Fe²⁺_0.4Y_0.2Ca_0.1Nb_0.75Ta_0.25O₄

Environment:

In pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1922

Locality:

Ishikawa, Ivaki Province, Japan. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Ishikawaite Image

Images:

Ishikawaite

Comments: Blocky, metamict crystals of ishikawaite.
Location: Spinelli Quarry (Spinelli prospect), South Glastonbury, Hartford Co., Connecticut, USA. Scale: 15x15x10 mm.
© John Betts - Fine Minerals

Ishikawaite Crystallography

Crystal System:

OrthorhombicSpace Group: Unk

Physical Properties of Ishikawaite

Cleavage:

None

Color:

Black.

Density:

6.2 - 6.4, Average = 6.3

Diaphaniety:

Opaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Metamict - Mineral originally crystalline, now amorphous due to radiation damage.

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Resinous

Streak:

dark brown

Optical Properties of Ishikawaite

Optical Data:

NCalc= 2.15 - from Gladstone-Dale relationship (KC = 0.1819) where Ncalc=Dmeas*KC+1

Calculated Properties of Ishikawaite

Electron Density:

r_electron=5.51 gm/cc
note: r_Ishikawaite=6.30 gm/cc.

Fermion Index

Fermion Index = 0.00349
Boson Index = 0.99651

Photoelectric:

PE_Ishikawaite= 858.78 barns/electron
U=PE_Ishikawaite x r_electron=4,733.22 barns/cc.

Radioactivity:

GRapi = 1,808,442.69 (Gamma Ray American Petroleum Institute Units)

Ishikawaite is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 10 cm box) 16.82 ± 4.20 grams of pure Ishikawaite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 1681.9 ±420.48 grams of pure Ishikawaite .

**Estimated Radioactivity from Ishikawaite** - very strong
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Bequerols (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 6.72 cm	43,410,131	1.17E-03	1,808,442.69	594.56
100 gm / 3.12 cm	4,341,013	1.17E-04	180,844.27	59.46
10 gm / 1.45 cm	434,101	1.17E-05	18,084.43	5.95
1 gm / 6.72 mm	43,410	1.17E-06	1,808.44	0.59
0.1 gm / 3.12 mm	4,341	1.17E-07	180.84	0.06
0.01 gm / 1.45 mm	434	1.17E-08	18.08	0.01
0.001 gm / 0.67 mm	43	1.17E-09	1.81	0.00

Weight of pure Ishikawaite in grams (gm) and Calculated Diameter of a Sphere with a Density of 6.30 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem

Ishikawaite Classification

Dana Class:

8.1.4.1 (8)Multiple Oxides with Nb, Ta, and Ti

(8.1)where A BO4

(8.1.4)Dana Group

8.1.4.1 Ishikawaite (U,Fe,Y,Ca)(Nb,Ta)O4(?) Unk Ortho

Strunz Class:

IV/D.19-70 IV - Oxides

IV/D - Oxides with metal : oxygen = 1:2 (MO2 and related compounds)

IV/D.19 - Polycrase-(Y) - Loranskite-(Y) series

IV/D.19-10 Polycrase-(Y) (Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6 Pcan 2/m 2/m 2/m

IV/D.19-15 Uranopolycrase (U,Y)(Ti,Nb,Ta)2O6 P bcn 2/m 2/m 2/m

IV/D.19-20 Yttrocrasite-(Y) (Y,Th,Ca,U)(Ti,Fe)2(O,OH)6 Unk Ortho

IV/D.19-30 Fersmite (Ca,Ce,Na)(Nb,Ta,Ti)2(O,OH,F)6 Pcan 2/m 2/m 2/m

IV/D.19-40 Euxenite-(Y) (Y,Ca,Ce)(Nb,Ta,Ti)2O6 Pcan 2/m 2/m 2/m

IV/D.19-60 Samarskite-(Y) (Y,Fe,U)(Nb,Ta)5O4 P bcn 2/m 2/m 2/m

IV/D.19-70 Ishikawaite (U,Fe,Y,Ca)(Nb,Ta)O4(?) Unk Ortho

IV/D.19-80 Yttrocolumbite-(Y) (Y,U,Fe)(Nb,Ta)O4 Unk Ortho

IV/D.19-90 Yttrotantalite-(Y) (Y,U,Fe)(Ta,Nb)O4 I2/a 2/m

IV/D.19-100 Loranskite-(Y) (Y,Ce,Ca)ZrTaO6(?) Unk Ortho

Other Ishikawaite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990)

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Ishikawaite

(U,Fe,Y,Ca)(Nb,Ta)O4 (?)
Dana No: 8.1.4.1 Strunz No: IV/D.19-70
Locality:

Notes: