Spodumene
Spodumene is a member of the Pyroxene Group of minerals that includes Aegirine, Diopside, Hedenbergite, Hypersthene, Jadeite, Petedunnite and Spodumene. Spodumene is also a member of the Spodumene Family of minerals that includesHiddenite, Kunzite, and Spodumene. It is a beautiful gem that is found as colorless, yellow, pale green, deep green (Hiddenite), pink (Kunzite), blue-green and, rarely, blue. Spodumene is strongly pleochroic, meaning it has a color intensity difference when viewed from different directions. It is a very difficult gem to facet because of its strong pleochroism, easy cleavage, and splintery fracture.
There are many localities for fine Spodumene crystals including Nuristan district, Laghman Province, Afghanistan; Minas Gerais, Brazil; Maharitra, Mt. Bity, and Anjanabonoina, Madagascar. In the USA, giant crystals in the Etta mine, near Keystone, Pennington County, South Dakota; at Hiddenite, Alexander County North Carolina; and from the Pala district, San Diego County, California.
| Category: | Inosilicate |
| Formula: | LiAl(SiO3)2 |
| lithium aluminium silicate | |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Spodumene: Crystals are prismatic, typically flattened and striated, to 12.5 m and 54 t. Commonly massive. |
| Twinning: | Common on [100]. |
| Cleavage: | [110] Good, [100] Good, [010] Partings |
| Fracture: | Uneven to Subconchoidal |
| Tenacity: | Brittle |
| Hardness (Mohs): | 6.5 – 7.0 |
| Density: | 3.03 – 3.23 (g/cm3) |
| Luminescence: | May show Yellow, Orange or Pink fluorescence under LW and SW UV. |
| Radioactivity: | Not Radioactive |
| Color: | Colorless, White, Gray, Yellow |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous, Dull; Pearly on cleavages |
| Refractive Index: | 1.648 – 1.679 Biaxial ( + ) |
| Birefringence: | 0.014 – 0.027 |
| Dispersion: | Weak; r < v; 0.012 |
| Pleochroism: | Distinct; X = Colorless; Y = Yellow; Z = Greenish Yellow |
