Alstonite Mineral Data

Alstonite Mineral Data +

General Alstonite Information

Chemical Formula:

BaCa(CO3)2

Composition:

Molecular Weight = 297.42 gm

Barium 46.17 % Ba 51.55 % BaO

Calcium 13.48 % Ca 18.85 % CaO

Carbon 8.08 % C 29.59 % CO₂

Oxygen 32.28 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

BaCa(CO₃)₂

Environment:

Low-temperature hydrothermal deposits. See other trimorphs paralstonite and barytocalcite.

IMA Status:

Valid Species (Pre-IMA) 1841

Locality:

Brownley Hill lead mine, Alston, Cumberland and Fallowfield lead mine hear Hexham, Northcumberland, England. Link to MinDat.org Location Data.

Name Origin:

Named after the locality.

Alstonite Image

Images:

Alstonite

Comments: Transparent alstonite crystals.
Location: Hexham, Northumberland, England. Scale: Size Not Given.
© Lou Perloff / Photo Atlas of Minerals

Alstonite Crystallography

Axial Ratios:

a:b:c =1.2069:1:0.4252

Cell Dimensions:

a = 17.38, b = 14.4, c = 6.123, Z = 10; alpha = 90.35°, beta = 90.12°, gamma = 120.08° V = 1,326.01 Den(Calc)= 3.72

Crystal System:

TriclinicSpace Group: P1 or P1

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

By Intensity(I/I_o): 3.55(1), 2.507(0.35), 2.05(0.23),

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Forms: [ 0 1 0] [ 2 2 1]

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Physical Properties of Alstonite

Cleavage:

[110] Imperfect

Color:

Colorless, Gray, White, Pink.

Density:

3.69 - 3.71, Average = 3.7

Diaphaniety:

Transparent to translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Habit:

Pseudo Hexagonal - Crystals show a hexagonal outline.

Hardness:

4-4.5 - Between Fluorite and Apatite

Luminescence:

Fluorescent, Long UV=weak yellow.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Alstonite

Gladstone-Dale:

CI meas= -0.002 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1675,KPDmeas= 0.1684,KC= 0.168

Optical Data:

Biaxial (-), a=1.526, b=1.671, g=1.672, bire=0.1460, 2V(Calc)=8, 2V(Meas)=6. Dispersion r > v weak.

Calculated Properties of Alstonite

Electron Density:

r_electron=3.38 gm/cc
note: r_Alstonite=3.70 gm/cc.

Fermion Index

Fermion Index = 0.08351
Boson Index = 0.91649

Photoelectric:

PE_Alstonite= 204.28 barns/electron
U=PE_Alstonite x r_electron= 691.22 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Alstonite is Not Radioactive

Alstonite Classification

Dana Class:

14.2.5.1 (14)Anhydrous Carbonates

(14.2)with Compound Formula A+ B++ (CO3)2

(14.2.5)Dana Group

14.2.5.1 Alstonite BaCa(CO3)2 P1 or P1 Tri

Strunz Class:

V/B.04-50 V - Nitrates, Carbonates and Borates

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

V/B.04 - Aragonite group

V/B.04-10 Aragonite CaCO3 Pmcn 2/m 2/m 2/m

V/B.04-20 Strontianite SrCO3 Pmcn 2/m 2/m 2/m

V/B.04-30 Witherite BaCO3 Pmcn 2/m 2/m 2/m

V/B.04-40 Cerussite PbCO3 Pmcn 2/m 2/m 2/m

V/B.04-50 Alstonite BaCa(CO3)2 P1 or P1 Tri

V/B.04-60 Barytocalcite BaCa(CO3)2 P 2₁ 2

V/B.04-65 Olekminskite Sr(Sr,Ca,Ba)(CO3)2 P 3₂1 3 2

V/B.04-70 Paralstonite BaCa(CO3)2 P 3₂1 3 2

Other Alstonite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

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

Alstonite

BaCa(CO3)2
Dana No: 14.2.5.1 Strunz No: V/B.04-50
Locality:

Notes: