Mineralogy Database

Steacyite Mineral Data

Search Webmineral :
  
Advertisment

General Steacyite Information

Help on Chemical  Formula: Chemical Formula: K1-x(Ca,Na)2ThSi8O20 (x=0.2 to 0.4)
Help on Composition: Composition: Molecular Weight = 825.70 gm
   Potassium   2.84 %  K     3.42 % K2O
   Sodium      1.95 %  Na    2.63 % Na2O
   Calcium     3.40 %  Ca    4.75 % CaO
   Thorium    25.29 %  Th   28.78 % ThO2
   Manganese   1.33 %  Mn    1.72 % MnO
   Silicon    27.21 %  Si   58.21 % SiO2
   Oxygen     37.98 %  O
             ______        ______ 
             100.00 %       99.52 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: K0.6Na0.7Ca0.7Mn2+0.2Th0.9Si8O19.6
Help on Environment: Environment: In cavities in pegmatite veins in nepheline syenite.
Help on IMA Status: IMA Status: Approved IMA 1982
Help on Locality: Locality: Mont Saint-Hilaire, Quebec, Canada. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Harold R. Steacy, formerly Curator of the National Mineral Collection, Geological Survey of Canada, Ottawa, Canada.
Help on Name Pronunciation: Name Pronunciation: Steacyite + Pronunciation Say STEACYITE
Help on Synonym: Synonym: Desourdyite
 

Steacyite Image

Click Here for Larger   Image in a New Browser Window Images:
Click Here for Larger   Image

  Steacyite

Comments: Square prismatic crystal of steacyite on acicular aegirine.
Location: Mont St. Hilaire, Quebec, Canada. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Steacyite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:1.94854
Help on Cell Dimensions: Cell Dimensions: a = 7.58, c = 14.77, Z = 2; V = 848.63 Den(Calc)= 3.23
Help on Crystal System: Crystal System: Tetragonal - Ditetragonal Dipyramidal H-M Symbol (4/m 2/m 2/m) Space Group: P 4/mcc
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.38(1), 5.22(0.9), 7.32(0.9),
 

Physical Properties of Steacyite

Help on Cleavage: Cleavage: None
Help on Color: Color: Brown, Yellow green.
Help on Density: Density: 2.95
Help on Diaphaneity: Diaphaneity: Translucent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Habit: Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Help on Hardness: Hardness: 5 - Apatite
Help on Luminescence: Luminescence: Radioactive.
Help on Luster: Luster: Vitreous - Dull
Help on Streak: Streak: white
 

Optical Properties of Steacyite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.001 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.087 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1772,KPDmeas= 0.1941,KC= 0.1942
Ncalc = 1.57 - 1.63
Help on Optical Data: Optical Data: Uniaxial (-), e=1.572, w=1.573, bire=0.0010.
 

Calculated Properties of Steacyite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.77 gm/cc
note: Specific Gravity of Steacyite =2.95 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PESteacyite = 568.46 barns/electron
U=PESteacyite x relectron=1,575.62 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 506,988.54 (Gamma Ray American Petroleum Institute Units)
Concentration of Steacyite per GRapi unit =1,972.43 (PPB)

Steacyite 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) 59.99 ± 15.00 grams of pure Steacyite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 5999.5 ±1499.9 grams of pure Steacyite .

Estimated Radioactivity from Steacyite - 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 / 8.65 cm 11,331,574 3.06E-04 506,988.54 166.68
100 gm / 4.02 cm 1,133,157 3.06E-05 50,698.85 16.67
10 gm / 1.86 cm 113,316 3.06E-06 5,069.89 1.67
1 gm / 8.65 mm 11,332 3.06E-07 506.99 0.17
0.1 gm / 4.02 mm 1,133 3.06E-08 50.70 0.02
0.01 gm / 1.86 mm 113 3.06E-09 5.07 0.00
0.001 gm / 0.87 mm 11 3.06E-10 0.51 0.00

Weight of pure Steacyite in grams (gm) and Calculated Diameter of a Sphere with a Density of 2.95 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
 

Steacyite Classification

Help on  Dana Class: Dana Class: 63.01.01.01 (63)Cyclosilicate Condensed Rings
  (63.01)4-membered rings
  (63.01.01)Steacyite Group
 
63.01.01.01 Steacyite K1-x(Ca,Na)2ThSi8O20(x=0.2to0.4) P 4/mcc 4/m 2/m 2/m
 
63.01.01.02 Iraqite-(La) K(La,Ce,Th)2(Ca,Na)4(Si,Al)16O40 P 4/mcc 4/m 2/m 2/m
 
63.01.01.03 Turkestanite! Th(Ca,Na)2(K1-x,[]x)Si8O20•n(H2O) P 4/mcc 4/m 2/m 2/m
 
63.01.01.04 Arapovite! (U,Th)(Ca,Na)2(K1-x[]x)Si8O20•H2O,x=0.5 P 4/mcc 4/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.CH.10 09 - SILICATES (Germanates)
  09.C - Cyclosilicates
  09.CH -[Si4O12]8- 4-membered double rings
 
09.CH.10 Iraqite-(La) K(La,Ce,Th)2(Ca,Na)4(Si,Al)16O40 P 4/mcc 4/m 2/m 2/m
 
09.CH.10 Steacyite K1-x(Ca,Na)2ThSi8O20(x=0.2to0.4) P 4/mcc 4/m 2/m 2/m
 
09.CH.10 Turkestanite! Th(Ca,Na)2(K1-x,[]x)Si8O20•n(H2O) P 4/mcc 4/m 2/m 2/m
 
09.CH.10 Arapovite! (U,Th)(Ca,Na)2(K1-x[]x)Si8O20•H2O,x=0.5 P 4/mcc 4/m 2/m 2/m
 

Other Steacyite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(AntBidBlaNic2)
Help on See Also: See Also: Links to other databases for Steacyite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - Uranium Minerals

Search for Steacyite using:

Google
 
Web webmineral.com
[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Steacyite :

Ask about Steacyite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Espaņol

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

Steacyite

K1-x(Ca,Na)2ThSi8O20 (x=0.2 to 0.4)
Dana No: 63.01.01.01 Strunz No: 09.CH.10
Locality:

 

Notes:

 

 
   
 


Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.