Garronite-Ca
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| Garronite-Ca | |
|---|---|
 Garronite-Ca. Group of crystals in oriented growth. Quarry of Barranc Salat, Calpe (Alicante) Spain. Group height 11 mm. | |
| General | |
| Category | Tectosilicate minerals |
| Group | Zeolite group |
| Formula | Na2Ca5Al12Si20O64·27H2O |
| IMA symbol | Grn-Ca[1] |
| Crystal system | Tetragonal |
| Crystal class | 32m |
| Identification | |
| Color | White |
| Crystal habit | Typically rhombohedral crystals saddle-shaped, twisted |
| Cleavage | ] |
| Mohs scale hardness | 4-5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Translucent |
| Specific gravity | 2,2 |
| References | [2][3] |
Garronite-Ca is a fairly rare silicate mineral, from the zeolite, which has been found in a few dozen locations in the world. It was first found in the Glenariff Valley, Garron Plateau, County Antrim, Northern Ireland, and in some locations in Iceland. The name comes from the town of Garron, in Northern Ireland, which is consequently considered its type locality.[4] The name initially used was that of Garronite, without subfixes, but the discovery in 2015 of a garronite with dominant sodium instead of calcium in the position of interchangeable cations made it necessary to use subfixes, remaining as Garronite-Ca, to distinguish it from the new species, Garronite-Na.[5]