Fluorcanasite

Fluorcanasite is a rare calcium, potassium, sodium fluoride silicate mineral, discovered in the Kirovsk mine's dumps, in Russia. It has been approved by the IMA in 2007. The name fluorcanasite is a portmanteau word, and was made by blending fluorine, a chemical element that can be found in the mineral, and canasite, as the mineral is close to canasite in several ways (analogue of said mineral and a member of the canasite group). Fluorcanasite is also close to frankamenite.[1]

Fluorcanasite
General
CategoryMineral
Formula
(repeating unit)		K3Na3Ca5Si12O30F4•H2O
Strunz classification09.DG.80
Dana classification78.05.04.02
Crystal systemMonoclinic
Crystal classDomatic (m)
Space groupBm
Unit cell1,602.59 ų
Identification
Formula mass1,297.67 gm
ColorLight Yellow
CleavageEminent on {100} and {201}
Perfect on {001}
FractureHackly, Step-like
TenacityBrittle
Mohs scale hardness5
LusterVitreous
StreakWhite
DiaphaneityTransparent
Specific gravity2.68
DensityMeasured 2.68(2)
Calculated 2.69
Optical propertiesBiaxial (+)
Refractive indexnα = 1.538(1)
nβ = 1.546(1)
nγ = 1.549(1)
Birefringence0.011
PleochroismStrong
2V angleMeasured 60° (2)
Calculated 63°
DispersionMedium
r > v
Ultraviolet fluorescenceNone
SolubilitySlowly decomposes in acid
Other characteristics Radioactive 0.77% (K)

Properties

It is the triclinic analogue of canasite, and a member of the canasite group. It grows into prismatic crystals that can reach up to 2 mms in size extending along [010]. It is pleochroic, meaning the color of the mineral seems to change depending on the axis it is viewed at. It is coloured amber, purple and lilac respectively along the α, β and γ optical axes.[1] It has a barely detectable 0.77% potassium radioactivity measured by the GRapi (Gamma Ray American Petroleum Institute Units). It consists mostly of oxygen (38.22%), silicon (25.97%) and calcium (15.44%), but otherwise contains potassium (9.04%) - which gives its radioactive attributes - fluorine (5.86%) and sodium (5.31%).[2] Parting is parallel to {001}. Hackly fracture only applies on the b axis, among a and c axis the fracture is stepped.[3]

Occurrences and localities

Fluorcanasite is a type locality at Mount Kukisvumchorr, Russia.[2] It is associated with pectolite, microcline, nepheline, villiaumite, scherbakovite, rasvumite, lamprophyllite, mosandrite, molybdenite and aegirine.[1]

References
  1. Khomyakov, A. P.; Nechelyustov, G. N.; Krivokoneva, G. K.; Rastsvetaeva, R. K.; Rozenberg, K. A.; Rozhdestvenskaya, I. V. (2009-12-01). "Fluorcanasite, K3Na3Ca5Si12O30(F,OH)4 · H2O, a new mineral species from the Khibiny alkaline pluton, Kola Peninsula, Russia, and new data on canasite". Geology of Ore Deposits. 51 (8): 757–766. Bibcode:2009GeoOD..51..757K. doi:10.1134/S107570150908008X. S2CID 93274455. Retrieved 2020-12-25.
  2. "Fluorcanasite Mineral Data". webmineral.com. Retrieved 2021-06-22.
  3. "Fluorcanasite". www.mindat.org. Retrieved 2022-04-11.
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