Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Tetragonal
    Chemistry : Na₄Al₃Si₉O₂4Cl to Ca₄Al₆Si₆O₂₄CO₃
    Rarity : Quite common

The term scapolite (or wernerite), which formerly designated a species, now corresponds to a group, chemically close to feldspar, composed essentially of 2 minerals : meionite (calcium) and marialite (sodium). These two minerals form a complete solid solution with the dipyre (80% to 50% Na) and mizzonite (80% to 50% Ca) as an intermediate variety. Its name comes from the Greek skapos (rod, stick) and lithos (stone), alluding to its elongated shape of its prismatic crystals. The formulas of marialite and meionite recall those of the two poles of the plagioclases, albite and anorthite, with additions of NaCl and CaSO₄. The structure is identical to that of feldspathoids. The species of this group appear mainly in the regional metamorphism from amphibolite facies to granulite facies ; they are also known in contact metamorphism (limestone enclaves in lavas or in reaction products between basic rocks and more acidic magma (pegmatoïd), and as a product of plagioclase alteration).

Marialite : its color is variable: colorless, white, gray, bluish, greenish, yellow, pink, purple... The crystals are prismatic, with an octagonal outline, striated parallel to [001], and with very often endings in flattened pyramids ; they can reach 1.5 meter s! Pure marialite is very rare and most specimens are intermediate terms marialite-meionite.

Meionite : its color is variable, usually yellowish to green, it can be colorless, white, rarely pink or purple. The crystals are prismatic, with an octagonal outline, striated parallel to [001], and at the ends very often in flattened pyramids; they can reach 70 cm. Pure meionite is very rare and most specimens are intermediate terms marialite-meionite.

The scapolite remains relatively unknown to mineral collectors, it is sometimes cut for jewelry.

In France, the largest crystals come from Casteroulot de Charot, Betchat (Ariège), they are transformed into quartz, albite, clinochlore and calcite and can exceed 10 cm.

No twinning known for this mineral species.

Rumors circulate on the web concerning the improvement of the color of certain scapolites by irradiation, however this treatment is currently not demonstrated. The color of some scapolite is not stable, the crystals can lose their color quickly if exposed to direct sunlight.