Formula: Na(AlSi₂O₆) · H₂O

Species:

Colour: White, colourless, gray, pink, green, yellow

Lustre: Vitreous, Sub-Vitreous, Dull

Hardness: 5 – 5½

Specific Gravity: 2.24 – 2.29

Crystal System: Triclinic

Member of: Zeolite Group

Name: First described by the french geologist Déodat de Dolomieu (1750-1801) as zéolithe dure [hard zeolite] in lava from the Cyclopean Islands near Sicily, Italy. Named in 1797 by the french mineraloguist Rene Just Haüy from the Greek ανάλκιμος (“analkimos”), “weak” or “without force”, alluding to weak electrostatic charge developed when the mineral is heated or rubbed.

Type Locality: Cyclopean Islands (Cyclopean Isles), Aci Trezza (Acitrezza), Aci Castello, Etna Volcanic Complex, Metropolitan City of Catania, Sicily – Italy

Zeolite Group. Analcime-Pollucite Series and the Analcime-Wairakite Series. The sodium analogue of Pollucite. The mineral occurs in multiple crystal systems.