7.4" Prehnite Crystal Cluster with Gyrolite & Apophyllite - India

This is an excellent prehnite pseudomorph cast after laumontite, found in Bombay, India. Small fibrous white balls of gyrolite and colorless apophyllite crystals can be found peppered across the light green prehnite. This is a truly gorgeous mineral formation that would make a great addition to any mineral collection.

Prehnite is a calcium aluminum silicate with the chemical composition Ca2Al(AlSi3O10)(OH)2. It generally occurs as volcanic cavity infillings. It often displays colors between yellow and green, but colorless and blue specimens are not unheard of.

This specimen comes from the Deccan Traps, a large igneous province and one of the largest volcanic features on Earth, in the Pune Province of western India. In the course of quarrying for other materials or digging wells, sometimes large pockets of zeolites and other minerals are unearthed in the volcanic rock.

Apophyllite, while not a zeolite itself, is almost always found associated with zeolites in the same pockets. It has two crystal habits: a rectangular prism capped by a steep four-sided pyramid, or a pseudo-cubic structure. While not a well-known mineral to the general public, it is popular among mineral collectors due to its pastel colors and beautiful crystal formations.

Prehnite, Apophyllite & Gyrolite
Mumbai (Bombay) District, Maharashtra, India
7.4 x 5.3"