Balliranoite

Balliranoite ((Na,K)6Ca2(Si6Al6O24)Cl2(CO)3) is a mineral that was discovered at Monte Somma – Vesuvio volcanic complex, Campania, Italy. This mineral is named in honor of Paolo Ballirano (b. 1964), Italian crystallographer and professor in the Department of Earth Sciences, University of Rome ‘‘La Sapienza’’, who has made important contributions to the crystal chemistry of cancrinite-group minerals.

Balliranoite
General
CategoryTectosilicates
Formula
(repeating unit)
(Na,K)6Ca2(Si6Al6O24)Cl2(CO3)
IMA symbolBlr[1]
Crystal systemHexagonal
Crystal class6 - Pyramidal
Space groupP63
Unit cella = 12.696 Å, c = 5.327 Å, V = 743.6 Å3, Z = 1
Identification
ColorColorless
Crystal habitPrismatic
CleavagePerfect on (10-10)
FractureIrregular/Uneven
TenacityBrittle
Mohs scale hardness5
LusterVitreous
StreakWhite
Density2.48 g/cm3
Optical propertiesuniaxial positive
References[2][3][4]

OccurrenceEdit

Balliranoite is found in an alkaline skarnlike rock composed of orthoclase, phlogopite, clinohumite, calcite, diopside, pargasite, haüyne, apatite and balliranoite,[5] as product of the metasomatic interactions between alkaline magma and limestone. These chemical alterations by hydrothermal and other fluids replace elements in the chemical structure, changing the mineral composition of the rock.

Mineral propertiesEdit

The idealized formula for balliranoite is (Na,K)6Ca2(Si6Al6O24)Cl2(CO3), and the empirical formula based on 12 Si atoms with isomorphic substitution by Al atoms is: Na4.70Ca2.53K0.73(Si6.02Al5.98O23.995)Cl2.34(CO3)0.82(SO40.27*0.12H2O.[3] This is a uniaxial (+) mineral with w = 1.523(2), e = 1.525(2), composed of the following compounds:[3]

Compound wt% Range
Na2O 13.05 12.80-13.24
K2O 3.08 3.01-3.16
CaO 12.70 12.56-12.85
Al2O3 27.28 27.17-27.42
SiO2 32.38 32.23-32.55
CO2 3.24 3.18-3.30
SO3 1.96 1.79-2.10
Cl 7.43 7.20-7.70
H2O 0.19 0.15-0.23
-O=Cl2 -1.68 -
Total 99.63 -

X-ray crystallographyEdit

The powder diffraction data for balliranoite is:

d-spacing (Å) Intensity
4.797 (100)
3.669 (57)
3.281 (73)
2.754 (16)
2.662 (58)
2.648 (13)
2.446 (31)
2.120 (18)

See alsoEdit

ReferencesEdit

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ E-Rock MinTreasure. 2020. England. Available in
  3. ^ a b c Chukanov, N.V., Zubkova, N.V., Pekov, I.V., Olysych, L.V., Bonaccorsi, E., Pushcharovsky, D.Yu (2010): Balliranoite, (Na,K)6Ca2(Si6Al6O24)Cl2(CO3), a new cancrinite-group mineral from Monte Somma - Vesuvio volcanic complex, Italy. European Journal of Mineralogy, 22, 113-119. Available in [1]
  4. ^ Hudson Institute of Mineralogy. 2021. Balliranoite. Mindat. Available in [2]
  5. ^ "Balliranoite". www.mindat.org.