Spinel
Spinel /ˈspɪnɛl/ is the magnesium aluminium member o the braider spinel group o minerall. It haes the formula MgAl2O4.[1] It wis kent i the bygane ruby ballas, miskent as bein sae like wae rubies an wis muckle socht efter for tae mak jowlry an ither sic plaister.
| Spinel | |
|---|---|
 Spinel. 4.13ct and 1.83ct. | |
| General | |
| Category | Oxide meenerals Spinel group Spinel structural group |
| Formula (repeatin unit) | MgAl2O4 |
| Strunz clessification | 04.BB.05 |
| Creestal seestem | Isometric |
| Identification | |
| Colour | Various; reid tae blue tae mauve, dark green, broun, black |
| Creestal habit | Cubic, octahedral |
| Cleavage | Indistinct |
| Fractur | Conchoidal, uneven |
| Mohs scale haurdness | 7.5–8.0 |
| Skinkle | Vitreous |
| Streak | White |
| Diaphaneity | Transparent tae translucent |
| Speceefic gravity | 3.6–4.1 |
| Optical properties | Isotropic |
| Refractive index | 1.719 |
| Pleochroism | Absent |
| Solubility | none |
| Ither chairacteristics | Nonmagnetic, non-radioactive, sometimes fluorescent (reid) |
| References | [1][2] |