Sérandite
Sérandite is an extremely rare gem that is one of the best known rare minerals from Mont Saint-Hilaire, Quebec, Canada. It contains manganese which gives it the beautiful salmon pink color similar to other manganese containing minerals such as Rhodochrosite and Rhodonite. Sérandite is often associated with other rare minerals such as Aegirine,Analcime, Arfvedsonite, Astrophyllite, Eudialyte, Nepheline, Sodalite and Villiaumite. Sérandite crystals are rarely transparent in large enough sizes for faceting, so faceted gems are usually translucent and included.
The main source of gemmy, translucent Sérandite crystals is the Poudrette quarry, Mont Saint-Hilaire, Rouville County, Québec, Canada.
| Category: | Inosilicates |
| Formula: | Na(Mn2+,Ca)2Si3O8(OH) |
| Crystallography: | Triclinic – Pinacoidal |
| Crystal Habit: | Prismatic to acicular crystals, elongated along [010]; bladed, blocky, or tabular crystals, flattened on [100], to 20 cm. As radiating crystal aggregates; massive. |
| Twinning: | Around [010], with composition plane [100]; less commonly contact twinned by reflection on [110]. |
| Cleavage: | [100] Perfect, [001] Perfect |
| Fracture: | Irregular/Uneven to Splintery |
| Tenacity: | Brittle |
| Hardness (Mohs): | 5.0 – 5.5 |
| Density: | 3.34 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Pale Pink, Salmon-Red, Salmon-Orange, deep Orange, Rose-Red, Brown, Colorless |
| Transparency: | Translucent to Transparent |
| Luster: | Vitreous, Greasy; fibrous aggregates are Dull to Silky |
| Refractive Index: | 1.668 – 1.703 Biaxial ( + ) |
| Birefringence: | 0.0250 – 0.0360 |
| Dispersion: | Moderate; r < v |
| Pleochroism: | None |
