Formula: Na₄(Si₈Al₄O₂₄] · 11H₂O

Species:

Colour: Colorless, white, reddish white, salmon-red, yellowish, greenish white

Lustre: Vitreous

Hardness: 4½

Specific Gravity: 2.02 – 2.17

Crystal System: Hexagonal

Member of: Gmelinite Group > Zeolite Group

Name: Named by David Brewster in 1825 in honor of the mineralogist and professor of chemistry, Christian Gottlob Gmelin (1792-1860) of the University of Tübingen, Germany. The suffix indicates the dominant extra-framework cation. In 1997, the name gmelinite (without suffix) was promoted from species to series and gmelinite-Na was defined as one of several species. The two others are Gmelinite-K and Gmelinite-Ca.

Type Locality: Monte Nero, San Pietro, Montecchio Maggiore, Vicenza Province, Veneto – Italy