| Stilbite | |
|---|---|
 | |
| General | |
| Category | Tectosilicate, Zeolite |
| Formula (repeating unit) | Stilbite-Ca: NaCa4(Si27Al9)O72·28(H2O) Stilbite-Na: Na9(Si27Al9)O72·28(H2O) |
| IMA symbol | Stb[1] |
| Strunz classification | 9.GE.10 (10 ed) 8/J.23-30 (8 ed) |
| Dana classification | 77.1.4.3 |
| Crystal system | Monoclinic, also triclinic and orthorhombic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/m (monoclinic) Amma (orthorhombic) |
| Identification | |
| Formula mass | Stilbite-Ca: 2,840 g/mol Stilbite-Na: 2,864 g/mol |
| Color | Usually colorless, white or pink |
| Crystal habit | Thin tabular, aggregates sheaf-like or in bow-ties, also fibrous and globular. |
| Twinning | Very common on {001} |
| Cleavage | Perfect on {010} |
| Fracture | Conchoidal or uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 3+1⁄2 to 4 |
| Luster | Vitreous, pearly on {010} |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 2.12 to 2.22 |
| Optical properties | Biaxial (−) |
| Refractive index | Nx = 1.479 to 1.492, Ny = 1.485 to 1.500, Nz = 1.489 to 1.505[2][3] Nx = 1.484 to 1.500, Ny = 1.492 to 1.507, Nz = 1.494 to 1.513[4][5] |
| Fusibility | Easily fused by blowpipe (~1050 °C) to produce a white "enamel"[6] |
| Solubility | Decomposes in HCl[6] |
| References | [3][4] [8][9] [10][11] |
Stilbite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, stilbite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named:
- Stilbite-Ca
- Stilbite-Na
Stilbite-Ca, by far the more common of the two, is a hydrous calcium sodium and aluminium silicate, NaCa4(Si27Al9)O72·28(H2O). In the case of stilbite-Na, sodium dominates over calcium. The species are visually indistinguishable, and the series name stilbite is still used whenever testing has not been performed.
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Rudy W. Tschernich (1992) Zeolites of the World. Geoscience Press
- ^ a b "Stilbite-Ca Mineral Data".
- ^ a b http://www.mindat.org/min-7313.html stilbite-Ca
- ^ a b "Archived copy" (PDF). Archived from the original (PDF) on 2020-03-29. Retrieved 2010-07-29.
{{cite web}}: CS1 maint: archived copy as title (link) - ^ a b Klein, Cornelis and Cornelius S. Hurlbut, 1985, Manual of Mineralogy, Wiley, pp. 465–466 ISBN 0-471-80580-7
- ^ Gaines et al (1997) Dana’s New Mineralogy Eighth Edition. Wiley
- ^ http://www.mindat.org/min-7314.html stilbite-Na
- ^ "Stilbite-Na Mineral Data".
- ^ Slaughter, M. (1970). "Crystal structure of stilbite". American Mineralogist. 55: 387–397. Retrieved 30 December 2020.
- ^ Cruciani, Giuseppe; Artioli, Gilberto; Gualtieri, Alessandro; Stahl, Kenny; Hanson, Jonathan C. (1 August 1997). "Dehydration dynamics of stilbite using synchrotron X-ray powder diffraction". American Mineralogist. 82 (7–8): 729–739. Bibcode:1997AmMin..82..729C. doi:10.2138/am-1997-7-810. S2CID 99122598.