Chemistry:
MESOLITE Na2Ca2Al6Si9O30 - 8H2O, Hydrated sodium calcium aluminum silicate
NATROLITE Na2Al2Si3O10-2H2O,
Hydrated sodium aluminum silicate
SCOLECITE CaAl2Si3O10-3H2O, Hydrated
calcium aluminum silicate
Class: Silicates
Subclass: Tectosilicates
Group: Zeolites
Color: clear or white.
Luster: vitreous to silky.
Transparency: crystals are
transparent to translucent.
Crystal System: monoclinic
Fracture: conchoidal.
Hardness: 5 - 5.5
Cleavage: perfect in two directions.
Specific Gravity: approximately 2.2
Streak: white.
PHYSICAL CHARACTERISTICS:
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. 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
Scolecite, a calcium zeolite, natrolite, a sodium zeolite, and
mesolite, a calcium and sodium zeolite, are closely related and sometimes
found together. The sodium in natrolite slightly
alters it's structure from the other two minerals. All three minerals
are referred to as "chain" or "needle" zeolites.
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.
Associated Minerals are quartz, apophyllite, babingtonite, heulandite,
stilbite and other zeolites.
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.
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.
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.
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MESOLITE - NATROLITE -
SCOLECITE
