Geology/History
Heulandite is a member of the zeolite group of hydrated tectosilicate minerals, most commonly found as a secondary mineral within the cavities of volcanic rocks such as basalts and andesites. It typically forms delicate, transparent to translucent crystals that are tabular, platy or coffin-shaped, often showing pearly lustre and subtle pastel colours ranging from white and colourless to pink, red, green or yellowish hues.
Heulandite was first described in 1818 and named in honour of the English mineralogist Henry Heuland (1778–1856), who contributed significantly to mineral collecting and the classification of zeolites. It was originally grouped with stilbite but later recognised as a distinct species based on its unique crystal structure and composition.
Heulandite is one of the most abundant zeolites found in nature. Well-known sources include the Deccan Traps in India, where beautiful, large, well-formed crystals fill geodes in volcanic rock. Other notable localities are Iceland, the Faroe Islands, Scotland, the United States and Italy. Though too soft and brittle for jewellery, Heulandite’s gentle lustre and delicate crystal forms make it highly desirable among collectors and mineral enthusiasts.
Zeolites like Heulandite also hold industrial significance as natural molecular sieves. Their ability to absorb and release water and trap ions makes them useful in water purification, soil conditioning and certain industrial processes.
Metaphysical Properties
Heulandite is widely regarded as a gentle stone of clarity, emotional healing and spiritual openness. It is said to facilitate deep meditation by helping quiet mental chatter and aligning the mind with higher states of awareness. Practitioners believe Heulandite can aid in recalling ancient memories and past life experiences, making it a popular stone for work involving spiritual journeys and inner exploration.
Aligned with the heart and crown chakras, Heulandite is thought to open the heart to forgiveness and compassion, dissolve negative emotional patterns and assist in releasing attachments to the past. It is said to encourage acceptance, calm anxiety and help one flow with change rather than resist it.
In spiritual traditions, Heulandite is believed to enhance the connection with spirit guides and angelic realms, acting as a subtle channel for receiving insights and intuitive messages.
Crystal Healing
Heulandite is thought to support the nervous system and to balance brain function, calming stress and overactivity. It is believed to soothe emotional tension, promote restful sleep and encourage emotional renewal. Some practitioners use Heulandite to aid memory recall, enhance dream work and deepen meditative states.
Mineralogy
Group: Zeolite
Crystal System: Monoclinic
Chemical Composition: (Ca,Na₂)₉[Al₁₈Si₂₇O₇₂]·24H₂O (Hydrated calcium sodium aluminium silicate)
Form/Habit: Tabular or platy crystals, coffin-shaped, often forming sheaf-like or radiating aggregates
Hardness: 3.5 to 4 (Mohs scale)
Cleavage: Perfect on {010}
Fracture: Uneven to subconchoidal
Lustre: Vitreous to pearly on cleavage surfaces
Streak: White
Specific Gravity: 2.2 to 2.4
Transparency: Transparent to translucent
Refractive Index (R.I.): 1.478 to 1.505
Birefringence: δ = 0.027
Colour: Colourless, white, pink, reddish, yellow, green or brownish
Pleochroism: None
Fluorescence: Generally none
Strunz Classification: 9.GE.15 (Silicates, Zeolites)
Dana Classification: 77.1.3.1 (Zeolites)