| Carletonite | |
| Formula: | KNa4Ca4(CO3)4Si8O18(F,OH)·(H2O) |
| Imasymbol: | Cto[1] |
| Strunz: | 9.EB.20 |
| System: | Tetragonal |
| Class: | Ditetragonal dipyramidal (4/mmm) H–M symbol: (4/m 2/m 2/m) |
| Symmetry: | P4/mbm |
| Unit Cell: | a = 13.17 Å, c = 16.69 Å; Z = 4 |
| Colour: | Colourless, light blue, dark blue, or pink |
| Habit: | Prismatic crystals, massive |
| Cleavage: | Perfect on, good on |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Mohs: | 4 - |
| Lustre: | Vitreous |
| Streak: | White |
| Diaphaneity: | Transparent to translucent |
| Gravity: | 2.45 |
| Opticalprop: | Uniaxial (-) |
| Refractive: | nω = 1.521 nε = 1.517 |
| Birefringence: | δ = 0.004 |
| Pleochroism: | Weak; O = pale blue; E = pale pinkish brown |
| References: | [2] [3] [4] [5] |
Carletonite is a rare silicate mineral with formula KNa4Ca4(CO3)4Si8O18(F,OH)·(H2O).
It is a phyllosilicate and a member of the apophyllite group. Its tetragonal crystals are a translucent blue, white, colorless or pink with a vitreous to dull lustre. It has a density of 2.45 and a hardness of 4–4.5.
It was discovered by G.Y Chao and named for the school he attended, Carleton University of Ottawa.[6] It was first described in 1969 for an occurrence at Mont Saint-Hilaire, Quebec. The type locality at Mont Saint–Hilaire is the only reported occurrence.[3] [4]
It occurs in hornfels and siliceous marble xenoliths within and adjacent to a nepheline syenite intrusion. It occurs in association with quartz, narsarsukite, calcite, fluorite, ancylite, molybdenite, leucosphenite, lorenzenite, galena, albite, pectolite, apophyllite, leifite, microcline and arfvedsonite.[3]