Balliranoite - Occurrence, Properties, and Distribution

Topics Covered

Introduction to Balliranoite
Properties of Balliranoite
Global Distribution
Occurrence of Balliranoite and Useful Mineral Association
References

Introduction to Balliranoite

Chemical Formula – (Na, K)₆Ca₂(Si₆Al₆O₂₄)Cl₂(CO₃)

Balliranoite, a member of the cancrinite group of minerals, has a hexagonal crystal system. It was named in honor of the Italian crystallographer Paolo Ballirano, Department of Earth Sciences at the University of Rome, for his contributions to the crystal chemistry of the cancrinite group of minerals.

Properties of Balliranoite

The following are the key properties of Balliranoite:

• Cell Data
  • Space Group: P6₃
  • a = 12.695(2)
  • c = 5.325(1)
  • Z = 1

• Crystal Data
  • Hexagonal
  • Point Group: 6
  • Crystals: prismatic on {101 0} and striated along [0001], to 2mm; as grains to 1cm
  • X-ray Powder Pattern - 4.797 (100), 3.281 (73), 2.662 (58), 3.669 (57), 2.446 (31), 2.120 (18), 2.754 (16)

• Chemical Composition

  Elements	Content
  SiO2	32.38
  Al2O3	27.28
  Na2O3	13.05
  CaO	12.7
  Cl	7.43
  CO2	3.24
  K2O	3.08
  SO3	1.96
  -O=Cl2	1.68
  H2O	0.19
  Total	99.63

• Optical Properties
  • Optical Class: Uniaxial (+)
  • ω = 1.523(2)
  • ε = 1.525(2)

Global Distribution

Balliranoite is widely distributed in Monte Somma–Vesuvio volcanic complex, Campania, Italy.

Occurrence of Balliranoite and Useful Mineral Association

Balliranoite occurs as a product of a metasomatic reaction between alkaline magma and limestone.

It is closely associated with apatite, hauyne, pargasite, diopside, calcite, clinohumite, phlogopite, and orthoclase.

References

• Balliranoite.pdf - Rruff Project Website - University of Arizona
• Balliranoite -Mindat