PHYSICAL PROPERTIES:
Class: Silicates
Subclass: Tectosilicates
Group: Zeolites
Crystal System: monoclinic
Fracture: conchoidal
Hardness: 5 - 5.5
Specific Gravity: approximately 2.2
Luster: vitreous to silky
Streak: White
Color: clear or white
Cleavage: perfect in two directions
Transparency: crystals are transparent to translucent.
Associated Minerals: quartz, apophyllite, Calcite, babingtonite, heulandite, stilbite and other zeolites.

COMPOSITION:
MESOLITE: Na2Ca2Al6Si9O30 - 8H2O, Hydrated sodium calcium aluminum silicate
NATROLITE: Na2Al2Si3O10-2H2O, Hydrated sodium aluminum silicate
SCOLECITE: CaAl2Si3O10-3H2O, Hydrated calcium aluminum silicate

DISTINGUISHING CHARACTERISTICS:
Scolecite and Mesolite are very much alike. They are zeolites which commonly exhibit an acicular or fibrous habit and there is virtually no distinction between the 2 minerals. The accepted rule generally assigns the name Mesolite to the very fine fibrous crystal specimens and Scolecite to the coarser crystal specimens. Although either name may appear on any Mesolite/Scolecite specimen

 
ENVIRONMENT:
These zeolites are somewhat rare in specimen form. Making them popular minerals among collectors. they form in volcanic bubbles called vesicles along with other zeolites.

CRYSTAL DESCRIPTION:
They are hard to distinguish when found in clusters with radiating, acicular habits. Natrolite tends to forms thin crystals with pyramidal terminations, but mesolite's fibrous crystals are usually the thinnest crystals of the three minerals. Scolecite's crystals tend to be the largest. These characteristics are only generalities. More extensive tests can be done for actural identification. These crystals can vary in size from almost hairlike to over 1 cm thick. They are easily damaged during removal or while being handled. So specimens are virtually impossible to attain without some minor crystal damage. Making perfect and near perfect specimens very valuable

LOCALITIES:
Poona, India; The Deccan basalt flows that cover 200,000 square miles of west central India are a prime source of fabulous zeolite specimens. In the above links we are featuring a Scolecite from the Nasik district of India and some fine Natrolite from Washington state.
Other locations include Riverside Co., and San Benito, California; New Jersey; Iceland;
Nova Scotia; Skye, Scotland and Santa Catarina, Brazil.

USES:
As mineral specimens and in chemical filtration. These zeolites have the typical zeolite structure. This structure has opeanings in it, that allow other ions and molecules to reside in and actually move around in these framework or "cage" structures. These structure contain open channels that allow water and large ions to travel into and out of the crystal structure.
The size of these channels controls the size of the molecules or ions and therefore, Zeolites
like these can act as chemical sieves.

FACTS & HISTORY:

Scolecite From the Greek, skolec = 'worm' in reference to the mineral's reaction to the blowpipe flame.

Natrolite From the Greek natron, "soda," in allusion to sodium content and lithos - "stone."

Mesolite The name comes from the Greek "mesos" meaning "middle" and "lithos" meaning "stone", because its composition falls between two other minerals, natrolite, and scolecite.