Serandite

Serandite is a rare sodium manganese calcium silicate mineral related to the wollastonite group, prized by collectors for its salmon-pink to peach crystals. Serandite forms in alkaline pegmatites and miarolitic cavities of nepheline syenite intrusions. These are rare igneous bodies where silica-undersaturated magmas concentrate sodium, manganese, and volatile elements into late-stage pegmatitic fluids. The Poudrette quarry at Mont Saint-Hilaire in Quebec is the world's primary and essentially only significant source of collector-grade serandite. This unusual alkaline intrusion has produced over 360 documented mineral species, making it one of the richest mineralogical localities on Earth. Serandite there crystallizes as pink prismatic crystals, often in druzy clusters, associated with analcime, aegirine, and catapleiite in late-stage cavities. The characteristic pink color comes from Mn²⁺ in the crystal structure, with deeper salmon tones in crystals richer in manganese relative to calcium. The species was named after J.M. Serand, a French mineral collector, by French mineralogist Alfred Lacroix in 1931 from original material collected on Los Islands off Guinea.

Serandite is immediately recognizable by its pink to salmon-pink color in prismatic crystals, often transparent at the tips and translucent through the body. The triclinic crystal system produces elongated bladed or prismatic forms with pinacoidal terminations. A key diagnostic property is bright salmon-pink fluorescence under longwave ultraviolet light, which no common pink mineral substitute shares. Specific gravity of 3.29-3.34 is noticeably heavy for a pink silicate. Hardness of 4.5-5 is modest, softer than feldspar. Vitreous to pearly luster on cleavage surfaces, with good cleavage parallel to the length of the crystals. The streak is white to pale pink. Most quality specimens are matrix pieces with serandite crystals nestled in druzy associations with clear analcime, black aegirine needles, and tabular white catapleiite.