Mordenite
Mordenite is a member of the Zeolite Group of minerals that includes over 40 minerals and these gem-type minerals: Analcime, Barrerite, Chabazite, Epistilbite, Gmelinite-Na, Goosecreekite, Mordenite, Natrolite, Pollucite, Scolecite, Stellerite, Stilbite, Thomsonite and Yugawaralite. Mordenite is not a rare mineral but it is very rarely available as a cabochon gem because it is typically found only as very fine, radiating needles or cottony aggregates. Cabochon gems do have a beautiful silky luster. It is available from many sources worldwide.
| Category: | Zeolite minerals |
| Formula: | (Ca, Na2, K2)Al2Si10O24·7H2O |
| Crystallography: | Orthorhombic – Pyramidal |
| Crystal Habit: | Prismatic crystals, elongated; acicular to fine fibrous, to 2.5 cm. In radiating groups or cottony aggregates; compact, porcelaneous. |
| Cleavage: | [100] Perfect, [010] Distinct |
| Fracture: | Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.0 – 5.0 |
| Density: | 2.10 – 2.15 (g/cm3) |
| Radioactivity: | Barely Detectable, GRapi = 6.53 (Gamma Ray American Petroleum Institute Units) |
| Color: | Colourless, White, Yellowish, Pinkish |
| Transparency: | Transparent to Translucent, Opaque |
| Luster: | Vitreous, Pearly, Silky if fibrous |
| Refractive Index: | 1.472 – 1.487 Biaxial ( + ) or ( – ) |
| Birefringence: | 0.005 |
| Dispersion: | None |
| Pleochroism: | None |
