Ten Rarest Gemstone In The World

Sérandite, also serandite,^[3] is a mineral with formula Na(Mn²⁺,Ca)₂Si₃O₈(OH). The mineral was discovered in Guinea in 1931 and named for J. M. Sérand. Sérandite is generally red, brown, black or colorless.

Sérandite was discovered on Rouma Island, part of the Los Islands in Guinea.^[2] The mineral was described by À. Lacroix in the journal Comptes Rendus hebdomadaires des séances de l’Académie des Sciences.He named it sérandite in honor of J.M. Sérand, a mineral collector who helped in the collection of the mineral

Sérandite is transparent to translucent and is normally salmon-pink, light pink, rose-red, orange, brown, black, or colorless; in thin section, it is colorless.^[1] Octahedrally bonded Mn(II) is the primary contributor to the mineral's pink colors.
Crystals of the mineral can be prismatic to acicular and elongated along [010], bladed, blocky, or tabular and flattened on {100}, occur as a radiating aggregate, or have massive habit.^[1] Sérandite is a member of the wollastonite group and is the manganese analogue of pectolite