Formula: (Ca,Na)₅(Si₂₇Al₉)O₇₂ · 26H₂O

Species:

Colour: White, colorless, red, yellow, brown, green

Lustre: Vitreous, Pearly

Hardness: 3½ – 4

Specific Gravity: 2.1 – 2.2

Crystal System: Monoclinic

Member of: Heulandite subgroup > Zeolite Group

Name: Named in 1822 by Henry James Brooke in honor of Johann Heinrich “John Henry” Heuland [1778 Germany – 1856 England], a mineral collector and mineral dealer living in England and for the suffix indicating dominant Ca. Despite having an international reputation, there are no known images of Henry Heuland.

Type Locality: Strathclyde, Scotland, UK

The calcium analogue of Heulandite-Ba, Heulandite-K, Heulandite-Na, and Heulandite-Sr.
Clinoptilolite-Ca-Heulandite-Ca Series.