Fluorcanasite
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Fluorcanasite is a rare calcium, potassium and sodium fluoride silicate mineral. It was discovered in 2003, in the Kirovsk mine's dumps in Russia, and was approved by the IMA in 2007.[1][2] The name fluorcanasite is a portmanteau, 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: it is an analogue of said mineral and a member of the canasite group.[3] Fluorcanasite is also close to frankamenite.[3]
| Fluorcanasite | |
|---|---|
| General | |
| Category | Minerals |
| Formula | 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) |
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 mm in size, extending along [010]. It is pleochroic, meaning that 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.[3] Parting is parallel to {001}.[2] Hackly fracture only occurs on the b axis; on a and c axis, the fracture is stepped.[2]
It consists mostly of oxygen (38.22%), silicon (25.97%) and calcium (15.44%), but also contains potassium (9.04%), fluorine (5.86%) and sodium (5.31%).[4] Its potassium content results in a barely detectable radioactivity level of 129.46 Gamma Ray American Petroleum Institute (GRapi) units and a concentration per GRapi unit of 0.77%.[4]
Occurrences and localities
Fluorcanasite is a type locality at Mount Kukisvumchorr, Russia.[4] It is associated with pectolite, microcline, nepheline, villiaumite, shcherbakovite, rasvumite, lamprophyllite, mosandrite, molybdenite and aegirine.[3]