Axinite is a brown to violet-brown, or reddish-brown bladed group of minerals composed of calcium aluminium boro-silicate, (Ca,Fe,Mn)3Al2BO3Si4O12OH. Axinite is pyroelectric and piezoelectric.

The axinite group includes:

  • Axinite-(Fe) or ferroaxinite, Ca2Fe2+Al2BOSi4O15(OH) iron rich, clove-brown, brown, plum-blue, pearl-gray[4]
  • Axinite-(Mg) or magnesioaxinite, Ca2MgAl2BOSi4O15(OH) magnesium rich, pale blue to pale violet; light brown to light pink[5]
  • Axinite-(Mn) or manganaxinite, Ca2Mn2+Al2BOSi4O15(OH) manganese rich, honey-yellow, clove-brown, brown to blue[6]
  • Tinzenite (CaFe2+Mn2+)3Al2BOSi4O15(OH) iron – manganese intermediate, yellow, brownish yellow-green[7]

Axinite is sometimes used as a gemstone.[8]

Gallery

  • Clove-brown axinite crystals to 2.3 cm set atop matrix from the West Bor Pit at Dalnegorsk, Russia
    Clove-brown axinite crystals to 2.3 cm set atop matrix from the West Bor Pit at Dalnegorsk, Russia
  • Chloritized bladed crystals of axinite forming on adularia from the Swiss Alps
    Chloritized bladed crystals of axinite forming on adularia from the Swiss Alps
  • Tinzenite on calcite, 4.5 × 3.5 × 3 cm. Wessels Mine, Kalahari manganese fields, Northern Cape Province, South Africa
    Tinzenite on calcite, 4.5 × 3.5 × 3 cm. Wessels Mine, Kalahari manganese fields, Northern Cape Province, South Africa
  • Manganaxinite (Axinite-(Mn)), with sharp curving crystals to 4 cm. West Bor Pit at Dalnegorsk, Russia
    Manganaxinite (Axinite-(Mn)), with sharp curving crystals to 4 cm. West Bor Pit at Dalnegorsk, Russia

References

  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. ^ Axinite Archived November 19, 2008, at the Wayback Machine. Mineral Galleries
  3. ^ Axinite. Mindat
  4. ^ Handbook of Mineralogy: Ferroaxinite
  5. ^ Handbook of Mineralogy: Magnesioaxinite
  6. ^ Handbook of Mineralogy: Manganaxinite
  7. ^ Handbook of Mineralogy: Tinzenite
  8. ^ Tables of Gemstone Identification By Roger Dedeyne, Ivo Quintens p.147