Bazzite

Bazzite is a beryllium scandium cyclosilicate mineral with chemical formula Be3Sc2Si6O18[3] (Be3(Sc,Fe)2Si6O18[4] or Be3(Sc,Al)2Si6O18[5]). It crystallizes in the hexagonal crystal system typically as small blue hexagonal crystals up to 2 cm length. It has a Mohs hardness of 6.5-7 and a specific gravity of 2.77 to 2.85.

Bazzite
Bazzite from Fibbia mountain, Fontana, Central St Gotthard Massif, Leventina, Ticino, Switzerland
General
CategoryCyclosilicate
Formula
(repeating unit)
Be3Sc2Si6O18
IMA symbolBz[1]
Strunz classification9.CJ.05
Crystal systemHexagonal
Crystal classDihexagonal dipyramidal (6/mmm)
H-M symbol: (6/m 2/m 2/m)
Space groupP6/mcc
Unit cella = 9.521 Å, c = 9.165 Å; Z = 2
Identification
ColorLight to dark sky-blue, blue green
Crystal habitAggregates of subparallel prisms
CleavageIndistinct on {0001}
FractureIrregular
TenacityBrittle
Mohs scale hardness6.5 - 7
LusterVitreous
StreakPale bluish white
DiaphaneitySemitransparent
Specific gravity2.77 - 2.85
Optical propertiesUniaxial (-)
Refractive indexnω = 1.622-1.637 nε = 1.602-1.622
Birefringence0.0210
PleochroismO = pale greenish yellow; E = intense sky-blue
References[2][3][4][5]

It is hard to distinguish from blue beryl.

Occurs in miarolitic cavities in granite, in alpine veins and in scandium bearing granitic pegmatites. It occurs associated with quartz, orthoclase, muscovite, laumontite, albite, hematite, calcite, chlorite, fluorite, beryl and bavenite.[4]

It was first described from an occurrence in Baveno, Italy. Named after the discoverer, the Italian engineer Alessandro E. Bazzi.[4]

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. Mineralienatlas
  3. Mindat with location data
  4. "Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2021-10-19. Retrieved 2013-01-07.
  5. Webmineral data


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