Analcime | |
Chemical Formula |
NaAlSi2O6·H2O |
Species |
Silicates |
Crystal System |
Triclinic |
Mohs Scale |
5 |
Specific Gravity |
2.24-2.29 |
Color |
White, colorless, gray, pink, greenish, yellowish |
Streak |
White |
Luster |
Vitreous |
Refractive Index |
n = 1.479 - 1.493 n = 1.480 - 1.494 |
Diaphaneity |
Transparent, Translucent |
Cleavage |
Poor/Indistincton |
Fracture |
Sub-Conchoidal |
Crystal Habit:Typically in crystals, usually trapezohedrons, also massive to granular. | |
Geological Setting:In the groundmass or vesicles of silica-poor intermediate and mafic igneous rocks, typically basalts and phonolites, from late-stage hydrothermal solutions, or disseminated due to deuteric alteration. In lake beds, altered from pyroclastics or clays, or as a primary precipitate; authigenic in sandstones and siltstones. |