Gregoryite Mineral Data

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)

IMA Status:

Approved IMA 1981

Locality:

Link to MinDat.org Location Data.

Gregoryite Image

Images:

Gregoryite Nyerereite

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 PyramidalH-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:

r_electron=2.42 gm/cc
note: r_Gregoryite=2.46 gm/cc.

Fermion Index

Fermion Index = 0.00141
Boson Index = 0.99859

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)

Estimated Radioactivity from Gregoryite - barely detectable

Gregoryite Classification

Dana Class:

14.1.2.2 (14)Anhydrous Carbonates

(14.1)with Simple Formula A+ CO3

(14.1.2)Dana Group

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

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

Strunz Class:

V/B.05-40 V - Nitrates, Carbonates and Borates

V/B - Waterfree carbonates [CO3]2- without unfamiliar anions

V/B.05 - Eitelie - Shortite - Carbocernaite series

V/B.05-10 Eitelite Na2Mg(CO3)2 R 3 3

V/B.05-20 Nyerereite Na2Ca(CO3)2 C mc2₁ mm2

V/B.05-30 Natrofairchildite Na2Ca(CO3)2 P 6₃/mmc 6/m 2/m 2/m

V/B.05-40 Gregoryite (Na2,K2,Ca)CO3 P 6₃mc 6mm

V/B.05-50 Fairchildite K2Ca(CO3)2 P 6₃/mmc 6/m 2/m 2/m

V/B.05-55 Zemkorite (Na,K)2Ca(CO3)2 P 6₃/mmc, P 6₃mc, P 6₂c- Hex

V/B.05-60 Butschliite K2Ca(CO3)2 R 3m 3 2/m

V/B.05-70 Shortite Na2Ca2(CO3)3 Amm2 mm2

V/B.05-80 Sahamalite-(Ce) (Mg,Fe)Ce2(CO3)4 P 2₁/a 2/m

V/B.05-90 Remondite-(Ce) Na3(Ce,La,Ca,Na,Sr)3(CO3)5 P 2₁ 2

V/B.05-92 Remondite-(La)! Na3(La,Ce,Ca)3(CO3)5 P 2₁ 2

V/B.05-95 Petersenite-(Ce) (Na,Ca)4(Ce,La,Nd)2(CO3)5 P 2₁ 2

V/B.05-98 Calcioburbankite Na3(Ca,REE,Sr)3(CO3)5 P 6₃mc 6mm

V/B.05-100 Burbankite (Na,Ca)3(Sr,Ba,Ce)3(CO3)5 P 6₃/mmc 6/m 2/m 2/m

V/B.05-110 Khanneshite (NaCa)3(Ba,Sr,Ce,Ca)3(CO3)5 P 6₃mc 6mm

V/B.05-120 Carbocernaite (Ca,Na)(Sr,Ce,Ba)(CO3)2 P mc2₁ mm2

Other Gregoryite Information

References:

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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Gregoryite

(Na2,K2,Ca)CO3
Dana No: 14.1.2.2 Strunz No: V/B.05-40
Locality:

Notes: