December 2025 – Analcime

Analcime is a widespread framework silicate and belongs to the mineral class of silicates and germanates. In its pure form, it appears colorless and transparent, but can be white, reddish, or yellowish in color due to light scattering or foreign admixtures.

Chemically, it is a hydrated sodium aluminosilicate. The mineral was first discovered in 1784 on the Cyclops Islands off Sicily and was given its current name in 1797 by René-Just Haüy.

Analcime occurs mainly in cavities in basic and intermediate rocks or as a transformation product of the mineral leucite, but can also crystallize directly from alkali-rich melts. With around 1700 known locations to date, it is one of the most common mineral formations worldwide.

Chemical formula: Na[AlSi₂O₆] · H₂O

Locality: Frombach, Seiser Alm, South Tyrol, Italy

Size: 7.5 x 14 x 12 cm (HxLxW)

Weight: 1100 g