Stellerite
Stellerite is one of the rarest members 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. Stellerite is chemically similar to Stilbite. Like Stilbite, Stellerite crystals can aggregate together to form a structure resembling wheat sheafs with the tops and bottoms of the crystal structure fanning out while the middle remains thin. The two often appear identical in crystal form but Stellerite is usually more transparent and colorless.
Stellerite is only found in small quantities from several locations worldwide including Copper Island, Komandorskiye (Commander) Islands, Bering Sea, and at Klichka, Chita region, Siberia, Russia. Fine examples in the Sarbayskaya quarry, near Rudniy, Kazakhstan. From Villanova Monteleone, Alghero, Sardinia, Italy. At Kongsberg, Norway. In the USA, at Ritter Hot Springs, Grant County, Oregon; on Hook Mountain, Rockland County, New York; and at Fanwood, Somerset County, New Jersey. In Australia, large crystals from around Gunnedah, New South Wales, and at Harcourt, Dookie, and Corop, Victoria. Exceptional examples from Cinchwad, Poona, and in the Nasik district, Maharashtra, India.
| Category: | Zeolite mineral |
| Formula: | Ca(Al2Si7O18)•7H20 |
| Crystallography: | Orthorhombic – Dipyramidal |
| Crystal Habit: | Single crystals show the forms [100], [010], [001], and [111]. Commonly in spheres, to 12 cm, of radiating crystals; as crystal aggregates. |
| Twinning: | None |
| Cleavage: | [010] Perfect, [100] Imperfect, [001] Imperfect |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Hardness (Mohs): | 4.5 |
| Density: | 2.12 – 2.13 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Colorless to White, Pink, Orange |
| Transparency: | Transparent to Translucent |
| Luster: | Pearly |
| Refractive Index: | 1.485 – 1.498 Biaxial ( – ) |
| Birefringence: | 0.0130 |
| Dispersion: | None |
| Pleochroism: | None |
