Minerals · common

Chabazite

Chabazite is a calcium-bearing zeolite mineral with the general formula (Ca,Na2,K2)Al2Si4O12·6H2O, known for its distinctive pseudo-cubic rhombohedral crystals that superficially resemble cubes. It forms in cavities within basaltic and volcanic rocks where hot, mineral-rich fluids circulate after the host lava cools, placing it among the classic zeolite minerals collected from vesicles in ancient lava flows. Its open, cage-like aluminosilicate framework allows it to absorb and exchange ions, a property shared with other zeolites and exploited in some industrial applications.

Photo: Robert M. Lavinsky · Wikimedia Commons · CC BY-SA 3.0

Chabazite properties at a glance

Type	Minerals
Chemical formula	CaAl2Si4O12·6H2O
Mohs hardness	4–5
Crystal system	Trigonal
Luster	Vitreous
Streak	White
Cleavage	Distinct rhombohedral
Fracture	Uneven
Specific gravity	2.05–2.15
Transparency	Transparent to translucent
Common colors	White, Colorless, Pink, Red, Yellow
Rarity	common

Geology & background

Chabazite crystallizes in the vesicles and fractures of basalt and related volcanic rocks as late-stage hydrothermal fluids cool, often growing alongside other zeolites such as stilbite, heulandite, and analcime. Classic localities include the Deccan Traps basalts of India, the Bay of Fundy region of Nova Scotia, Iceland's basalt plateaus, and the Faroe Islands, all places where thick lava sequences provided abundant cavities for slow crystal growth. Chabazite crystals often appear twinned, producing distinctive pseudo-hexagonal or interpenetrant forms that make them recognizable even to casual collectors.

Collectors are drawn to chabazite for its sharp, glassy rhombohedra, which can be colorless, white, pink, or brick-red depending on trace iron oxide staining from the surrounding basalt. Because it typically grows as isolated crystals or small clusters lining vugs rather than large masses, well-formed specimens with clean crystal faces are more desirable than broken or altered material, and Indian Deccan Trap specimens have become widely available and affordable in recent decades.

How to identify Chabazite

Chabazite typically occurs as colorless, white, yellow, pink, or reddish rhombohedral crystals with a vitreous to slightly pearly luster and a white streak. It has a hardness of 4 to 5 and cleavage that is imperfect in the rhombohedral direction, most often recognized by its pseudo-cubic crystal habit and characteristic penetration twins. It can be confused with calcite or other zeolites like gmelinite, but chabazite's lower density than calcite, lack of strong rhombohedral cleavage, and typical occurrence in basalt vugs help confirm its identity.

Compare the specimen's color, luster, crystal habit, grain size, streak, and locality before confirming.
Use multiple photos when possible, including a fresh surface and a close view of texture.

Where Chabazite is found

Reported from multiple localities worldwide; verify locality against specimen provenance when available.

How much is Chabazite worth?

Entry-level specimen	$2
Typical collector specimen	$20
Premium specimen	$150+

Value depends on size, crystal quality, color, locality, rarity, damage, and provenance.

Common uses

Collector specimens
Education
Field identification
Industrial or lapidary use when suitable

Interesting facts

Chabazite's crystal habit so closely mimics a cube that early mineralogists sometimes mistook it for a variety of calcite before its true zeolite structure was understood.
The porous aluminosilicate framework of chabazite allows it to selectively trap and release molecules, a property studied for gas separation and water purification.
Nova Scotia's Bay of Fundy basalts are one of the classic zeolite localities in North America, yielding chabazite alongside stilbite and analcime in the same cavities.