Gregoryite Mineral Data

General Gregoryite Information

Chemical Formula:

(Na2,K2,Ca)CO3

Composition:

Molecular Weight = 115.06 gm

Potassium 20.39 % K 24.56 % K₂O

Sodium 23.98 % Na 32.32 % Na₂O

Calcium 3.48 % Ca 4.87 % CaO

Carbon 10.44 % C 38.25 % CO₂

Oxygen 41.71 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

0.6(Na₂)0.3(K₂)Ca_0.1(CO₃)

Environment:

Phenocrysts in lengaite carbonatite lava.

IMA Status:

Approved IMA 1981

Locality:

Oldoinyo Lengai volcano, Tanzania. Link to MinDat.org Location Data.

Name Origin:

Named for John Walter Gregory (1864-1932), University of Melbourne, Melbourne, Australia and University of Glasgow, Glasgow, Scotland.

Name Pronunciation:

Gregoryite + Pronunciation

Gregoryite Image

Images:

Nyerereite Gregoryite

Comments: Sodium (nyereteite) and potassium (gregoryite) carbonates, not stable in normal atmosphere, collected molten from the volcano and maintained in inert argon atmosphere.
Location: Ol Doinyo Lengai Vulkan, Maasai Steppe, East Africa Rift Valley, Tanzania. See Link. Scale: Rock size 2 cm.
© Richard Dale / Dale Minerals

Gregoryite Crystallography

Axial Ratios:

a:c = 1:1.26251

Cell Dimensions:

a = 5.215, c = 6.584, Z = 2; V = 155.07 Den(Calc)= 2.46

Crystal System:

Hexagonal - Dihexagonal Pyramidal H-M Symbol (6mm) Space Group: P 6₃mc

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

By Intensity(I/I_o): 2.66(1), 2.61(0.75), 3.29(0.4),

Physical Properties of Gregoryite

Color:

White.

Density:

2.27

Streak:

white

Optical Properties of Gregoryite

Optical Data:

NCalc= 1.49 - from Gladstone-Dale relationship (KC = 0.2005) where Ncalc=Dcalc*KC+1
NCalc= 1.46 - from Gladstone-Dale relationship (KC = 0.2005) where Ncalc=Dmeas*KC+1

Calculated Properties of Gregoryite

Electron Density:

Bulk Density (Electron Density)=2.42 gm/cc
note: Specific Gravity of Gregoryite =2.46 gm/cc.

Fermion Index:

Fermion Index = 0.001419959
Boson Index = 0.998580041

Photoelectric:

PE_Gregoryite= 2.98 barns/electron
U=PE_Gregoryite x r_electron= 7.21 barns/cc.

Radioactivity:

GRapi = 289.43 (Gamma Ray American Petroleum Institute Units)
Concentration of Gregoryite per GRapi unit = 0.35 (%)

Estimated Radioactivity from Gregoryite - barely detectable

Gregoryite Classification

Dana Class:

14.01.02.02 (14)Anhydrous Carbonates

(14.01)with Simple Formula A+ CO3

(14.01.02)Vaterite Group

14.01.02.01 Vaterite CaCO3 P 6₃/mmc 6/m 2/m 2/m

14.01.02.02 Gregoryite (Na2,K2,Ca)CO3 P 6₃mc 6mm

Strunz Class:

05.AA.10 05 - CARBONATES (NITRATES)

05.A - Carbonates without additional anions, without H2O

05.AA -Alkali Carbonates

05.AA.10 Gregoryite (Na2,K2,Ca)CO3 P 6₃mc 6mm

05.AA.10 Natrite Na2CO3 C 2 or Cm Mono

Other Gregoryite Information

References:

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

See Also:

Links to other databases for Gregoryite :
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

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

Gregoryite

(Na2,K2,Ca)CO3
Dana No: 14.01.02.02 Strunz No: 05.AA.10
Locality:

Notes:

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