Back Spinel Afrikaans Espinela AN لعل (جوهرة) Arabic Şpinel Azerbaijani Шпінель Byelorussian Шпінэль BE-X-OLD Шпинел Bulgarian Espinel·la Catalan Spinel Czech Шпинель CV
| Spinel | |
|---|---|
 Small spinel crystal on top of a white calcite from Mogok, Myanmar, measuring 1.5 × 1.1 × 1 cm in size | |
| General | |
| Category |
|
| Formula (repeating unit) | MgAl 2O 4 |
| IMA symbol | Spl[1] |
| Strunz classification | 4.BB.05 |
| Crystal system | Cubic |
| Crystal class | Hextetrahedral (43m) H–M symbol: (43m)[2][3][4] |
| Space group | F 4 3 m (No. 216) |
| Unit cell | a = 8.0898(9) Å; Z = 8 |
| Identification | |
| Color | Various; red, pink, blue, lavender/violet, dark green, brown, black, colourless |
| Crystal habit | Octahedral or flat triangular plates caused by twinning |
| Twinning | common |
| Cleavage | None |
| Fracture | Conchoidal |
| Mohs scale hardness | 7.5–8.0 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to opaque |
| Specific gravity | (Depending on the composition) The rare Zn-rich spinel can be as high as 4.40, otherwise it averages from 3.58 to 3.61. |
| Optical properties | Isotropic |
| Refractive index | 1.719 |
| Pleochroism | Absent |
| Solubility | None |
| Other characteristics | Weak to medium magnetic, sometimes fluorescent (red synthetic yes, natural red sometimes) |
| References | [5][6] |
Spinel (/spɪˈnɛl, ˈspɪnəl/[7]) is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl
2O
4 in the cubic crystal system. Its name comes from the Latin word spinella, a diminutive form of spine, in reference to its pointed crystals.[5]
- ^ 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.
- ^ Robert John Lancashire. "Normal Spinels". CHEM2101 (C 21J) Inorganic Chemistry – Chemistry of Transition Metal Complexes. University of the West Indies. Archived from the original on 2018-08-08.
- ^ N. W. Grimes; et al. (Apr 8, 1983). "New Symmetry and Structure for Spinel". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. 386 (1791): 333–345. Bibcode:1983RSPSA.386..333G. doi:10.1098/rspa.1983.0039. JSTOR 2397417. S2CID 96560029.
- ^ L. Hwang; et al. (Jul 1973). "On the space group of MgAl
2O
4 spinel". Philosophical Magazine. doi:10.1080/14786437308217448. - ^ a b "Spinel". Mindat.org.
- ^ Spinel Mineral Data, WebMineral.com
- ^ "spinel". The Chambers Dictionary (9th ed.). Chambers. 2003. ISBN 0-550-10105-5.