Barrerite
Barrerite could be the member that is rarest of 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. The crystal system is orthorhombic and is flat and tubular in appearance.The mineral Barrerite was found in 1974 near Capo Pula, Sardinia, Italy. The only source that is current of quality crystals of Barrerite is on the Kuiu Island and Kupreanof Island, Alaska, USA. Gems are often colourless to very slightly translucent and red.
| Category: | Zeolite |
| Chemical Formula: | (Na,K,Ca)2Al2Si7O18 · 7H2O |
| Hydrated Potassium Sodium Calcium Aluminum Silicate | |
| Molecular Weight: | 2,680.57 gm |
| Composition: | Potassium | 1.55 % | K | 1.86 % | K2O |
| Sodium | 4.67 % | Na | 6.30 % | Na2O | |
| Calcium | 1.26 % | Ca | 1.76 % | CaO | |
| Magnesium | 0.15 % | Mg | 0.26 % | MgO | |
| Aluminum | 8.24 % | Al | 15.58 % | Al2O3 | |
| Iron | 0.02 % | Fe | 0.03 % | FeO | |
| Silicon | 23.80 % | Si | 50.93 % | SiO2 | |
| Hydrogen | 1.94 % | H | 17.33 % | H2O | |
| Oxygen | 58.36 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Orthorhombic – Dipyramidal |
| Crystal Habit: | As well-formed, laminar crystals, to 5 mm, with {010}, {011}, and {111}; {001} is common, but of poor quality. |
| Twinning: | None |
| Cleavage: | Perfect on {010} |
| Fracture: | Irregular/Uneven, Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.0 – 4.0 |
| Density: | 2.13 – 2.30 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Barely Detectable; GRapi = 22.57 (Gamma Ray American Petroleum Institute Units) |
| Color: | White, Pink |
| Transparency: | Transparent, Translucent |
| Luster: | Vitreous |
| Refractive Index: | 1.479 – 1.489 Biaxial ( – ) |
| Birefringence: | 0.010 |
| Dispersion: | None |
| Pleochroism: | None |
