Fluorcanasite
| Fluorcanasite | |
|---|---|
| General | |
| Category | Mineral |
| Formula (repeating unit) | K3Na3Ca5Si12O30F4•H2O |
| Strunz classification | 09.DG.80 |
| Dana classification | 78.05.04.02 |
| Crystal system | Monoclinic |
| Crystal class | Domatic (m) |
| Space group | Bm |
| Unit cell | 1,602.59 ų |
| Identification | |
| Formula mass | 1,297.67 gm |
| Color | Light Yellow |
| Cleavage | Eminent on {100} and {201} Perfect on {001} |
| Fracture | Hackly, Step-like |
| Tenacity | Brittle |
| Mohs scale hardness | 5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent |
| Specific gravity | 2.68 |
| Density | Measured 2.68(2) Calculated 2.69 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.538(1) nβ = 1.546(1) nγ = 1.549(1) |
| Birefringence | 0.011 |
| Pleochroism | Strong |
| 2V angle | Measured 60° (2) Calculated 63° |
| Dispersion | Medium r > v |
| Ultraviolet fluorescence | None |
| Solubility | Slowly decomposes in acid |
| Other characteristics |  Radioactive 0.77% (K) |
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]
Properties
[edit]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
[edit]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
[edit]- ^ a b c 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.
- ^ a b "Fluorcanasite Mineral Data". webmineral.com. Retrieved 2021-06-22.
- ^ "Fluorcanasite". www.mindat.org. Retrieved 2022-04-11.