Ishikawaite Mineral Data

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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.

Name Pronunciation:

Ishikawaite + Pronunciation

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

Diaphaneity:

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:

Bulk Density (Electron Density)=5.51 gm/cc
note: Specific Gravity of Ishikawaite =6.30 gm/cc.

Fermion Index:

Fermion Index = 0.003495602
Boson Index = 0.996504398

Photoelectric:

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

Radioactivity:

GRapi = 1,808,443.99 (Gamma Ray American Petroleum Institute Units)
Concentration of Ishikawaite per GRapi unit = 552.96 (PPB)

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 Becquerels (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	43,410,145	1.17E-03	1,808,443.99	594.56
100 gm / 3.12 cm	4,341,015	1.17E-04	180,844.40	59.46
10 gm / 1.45 cm	434,101	1.17E-05	18,084.44	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:

08.01.04.01 (08)Multiple Oxides with Nb, Ta, and Ti

(08.01)where A BO4

(08.01.04)Dana Group

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

Strunz Class:

04.DB.25 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DB -With medium-sized cations; chains of edge-sharing octahedra

04.DB.25 Ixiolite (Ta,Nb,Sn,Mn,Fe)O2 P 2/c 2/m

04.DB.25 Ishikawaite (U,Fe,Y,Ca)(Nb,Ta)O4(?) Unk Ortho

04.DB.25 Srilankite (Ti,Zr)O2 P bcn 2/m 2/m 2/m

04.DB.25 Samarskite-(Y) (Y,Fe,U)(Nb,Ta)5O4 P bcn 2/m 2/m 2/m

04.DB.25 Samarskite-(Yb)! (Yb,Y,REE,U,Th,Ca,Fe)(Nb,Ta,Ti)O4 P 2/c 2/m

04.DB.25 Yttrocolumbite-(Y) (Y,U,Fe)(Nb,Ta)O4 Unk Ortho

Other Ishikawaite Information

References:

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

See Also:

Links to other databases for Ishikawaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - Uranium Minerals

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Ask about Ishikawaite here :
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Mindat.org's Discussion Groups
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Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Ishikawaite

(U,Fe,Y,Ca)(Nb,Ta)O4 (?)
Dana No: 08.01.04.01 Strunz No: 04.DB.25
Locality:

Notes: