What is Quintinite?
Quintinite is a soft hydrotalcite-group carbonate with pearly white to pale-coloured platy crystals, valued for its layered structure and unusual magnesium-aluminium chemistry.
Mineralogy and crystal structure
Reference formula: Mg4Al2(OH)12CO3·3H2O. Quintinite is a layered hexagonal carbonate hydroxide hydrate. Polytype and stacking differences occur in the quintinite series, so the exact structure source and specimen locality should be retained. Quintinite is classified with carbonates and has a hexagonal crystal system. Typical hardness is 2–3 on the Mohs scale and specific gravity is approximately 2.0–2.2.
Colour, lustre and habit
Typical colours include white, cream, pale yellow, pink. The usual platy, micaceous, lamellar habit and pearly, vitreous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Quintinite forms in or is associated with carbonatites, alkaline complexes, hydrothermal environments and weathering zones rich in magnesium and aluminium. Important documented localities include alkaline and carbonatite-related occurrences in Canada, Russia, Italy and other documented localities.
Pearly layers from an alkaline rock system
Quintinite offers a refined collector story: a soft, micaceous-looking mineral records carbonate-rich alkaline fluids and layered crystal chemistry in a small, elegant specimen.
Collecting and care
Avoid acids, abrasion and prolonged soaking. Clean only with a soft dry brush or very gentle damp cloth, and protect the thin plates from bending and impact.
