A great Indian Prehnite Cluster for your collection. Prehnite is named after its discoverer Colonel Hendrik von Prehn. An attractive collection mineral that is occasionally used for ornamental stone purposes and jewelery. This particular specimen has the wonderful pale green green colour and prominent finger formations. The white little balls are Gyrolite and this specimen is mounted on a perspex pad for enhanced display.
Bombay Quarry, Mumbai District, Maharashtra, India.
9.1cm x 3.3cm x 8.4cm, 115g.
Calcium Aluminum Silicate Hydroxide
Ca2 Al2 Si3 O10(OH)2.
Prehnite is often found with zeolites and is sometimes thought of as a zeolite. Zeolites are Tectosilicates and Prehnite is a member the Phyllosilicates Subclass. Like zeolites, prehnite can give off water when heated, but can not gain the water back like they can. Like most zeolites, prehnite is formed as a result of low grade metamorphism usually from hydrothermal solutions. Crystals can be found in cavities of mafic igneous rocks.
Minerals that can be confused with prehnite include gyrolite, smithsonite and hemimorphite. Prehnite is harder than all of these and lacks smithsonite’s unusual luster. Hemimorphite is usually blue and gyrolite is not as glassy. Prehnite can be associated with many beautiful minerals and can make a fine specimen on its own. Its color, luster, associations and crystal habits make it a joy to own.