THE MINERAL CHABAZITE
- Chemistry: CaAl2Si4O12 - 6H2O, Hydrated calcium aluminum silicate
- Class: Silicates
- Subclass: Tektosilicates
- Group: Zeolites
- Uses: Mineral specimen and chemical filter.
Specimens
One vesicle, which can look like a geode, can have an amazing assortment of minerals and chabazite is sometimes a key component in these veritable mineral treasure troves. The mix may contain sprays of natrolite's or scolecite's bright, needle thin crystals, curved pink crystals of stilbite and blocky, pearly, coffin shaped crystals of huelandite. Included in this diverse mix and making its own marked distinction in character could be the angular, vitreous, pseudocubic crystals of chabazite.
The typical crystal of chabazite is a
Chabazite's structure has a typical zeolite openness that allows large ions and molecules to reside and actually move around inside the overall framework. The structure actually contains 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 a zeolite like chabazite can act as a chemical sieve, allowing some ions to pass through while blocking others.
PHYSICAL CHARACTERISTICS:
- Color is clear, white, pink, yellowish, reddish and brown.
- Luster is vitreous.
- Transparency: Crystals are transparent to translucent.
- Crystal System is trigonal; bar 3 2/m
- Crystal Habits include blocky rhombohedral crystals that can look cubic (pseudocubic) because the angle between the faces is nearly 90 degrees. Aggregates form crusts and granular masses. Twinning is common with the penetration twin rotated around the c-axis.
- Cleavage is poor in three directions parallel to the faces of the rhombohedron.
- Fracture is uneven.
- Hardness is 4 - 5.
- Specific Gravity is approximately 2.0 - 2.2 (very light)
- Streak is white.
- Other Characteristics: Unlike calcite, does not react to acids.
- Associated Minerals are quartz, calcite, scolecite, apophyllite, natrolite, heulandite, stilbite and other zeolites.
- Notable Occurrences include Poona, India; Berufjord, Iceland; Columbia Co., Oregon, Passaic Co., New Jersey and in Yellowstone Park, USA; Cumberland Co., Nova Scotia; New Zealand, Rhineland, Germany and Switzerland.
- Best Field Indicators are crystal habit and symmetry, density, hardness, luster, lack of reaction to acids and associations.
 Amethyst Galleries' Mineral Gallery MINERALS |
CHABAZITE specimen cha-1
$ 36.00
$ 36.00
Dims: 2.6" x 1.3" x 1.1" (6.6 x 3.3 x 2.8 cm)
Wt: 1.25 oz. (35.6 g)
Prospect Park, New Jersey, U.S.A.
Several rhombohedral Chabazite crystals rest on the quartz base of this specimen. They are in excellent condition with no evidence of any human-induced damage, and have good form, though five are intergrown and not completely formed . The largest crystal measures about 0.7" (1.8 cm) in all dimensions, and is the least complete and most intergrown of all of them. Several very small individual crystals are scattered around the intergrown cluster of larger ones. All have an orange-pink coloration, a pearly to vitreous luster, and are translucent, with small areas of transparence and many internal fractures. Along with the Chabazites are a few heulandite aggregates, one of which is complete and shows good form. They are white in color and translucent with a pearly luster. All of these rest on a druse of tiny transparent quartz crystals, which in turn rest on a thin layer of pale gray agate. The agate coats a thin skin of igneous rock that may have been part of the outer coating of a geode or vug.
cha-1 ($ 36.00)
Prospect Park, New Jersey, U.S.A.
CHABAZITE specimen cha-2
$ 26.00
$ 26.00
Dims: 2.0" x 1.3" x 1.0" (5.1 x 3.3 x 2.5 cm)
Wt: 26.4 g
Bashen Quarry, Waddamana, Tasmania, Australia
This thumbnail specimen is made up almost entirely of intergrown Chabazite crystals. Though there is some obvious breakage due to the specimen's separation from its host rock, most of the crystals are undamaged and in excellent condition. Though their intense intergrowth provides much interference, the crystals show a reasonably good trigonal prismatic form, and some appear to be double-terminated. The largest crystal has dimensions of 0.3 x 0.2 x 0.2" (8 x 5 x 5 mm) and like all the others, has a milky-white color and a vitreous-to-pearly luster. All are translucent but appear to be intensely internally-fractured. There does not seem to be any sort of host rock present on the piece.
cha-2 ($ 26.00)
Bashen Quarry, Waddamana, Tasmania, Australia
CHABAZITE specimen cha-3
$ 40.00
$ 40.00
Dims: 1.7" x 1.4" x 1.1" (4.3 x 3.6 x 2.8 cm)
Wt: 20.6 g
Bashen Quarry, Waddamana, Tasmania, Australia
This small specimen consists of a crust of intergrown Chabazite crystals that started to form a few small "outcroppings". The crystals that make up the crust reach maximum dimensions of 0.4 x 0.3 x 0.2" (1.0 x 0.8 x 0.5 cm), and are in very good condition, showing moderate damage. Their trigonal prismatic form is quite unusual, as all of the crystals have taken on a trigonal dipyramidal form; the pyramids are quite shallow, making me want to call them "trigonal tabular". Even with their intense intergrowth, this form is quite evident. There seem to be some definite planes of symmetry visible that suggest twinning. The crystals' edges are slightly rounded but still easily definable, and their faces are smooth and show a bright, pearly luster. All have a milky-white coloration that is caused by intense internal fracturing, which also spoils their clarity. There is no host rock or other material on the specimen- it is made up entirely of Chabazite.
cha-3 ($ 40.00)
Bashen Quarry, Waddamana, Tasmania, Australia
CHABAZITE specimen cha-4
$ 45.00
$ 45.00
Dims: 3.0" x 2.0" x 1.7" (7.6 x 5.1 x 4.3 cm)
Wt: 3.24 oz. (92.0 g)
Bashen Quarry, Waddamana, Tasmania, Australia
This rather intriguing specimen consists of a crust of massive-to-crystalline Chabazite that was separated from its base rock. The areas that bear crystals show trigonal bladed, "spearhead" crystals with a diamond-shaped cross-section. The largest of these do not exceed 0.4" (1.0 cm) in length. Though some of them are obviously broken, most are in excellent condition besides their apparent weathering. They all have a very pale blue-violet coloration and appear to be dirty, though their discoloration is likely caused by a coating of another mineral. Their worn state is shown also through their dull, almost matte luster, which is offset by the brighter, pearly luster of the breakage surfaces. All are at least translucent; though some may be even transparent, their dull luster prevents me from being sure. There is also a bit of rust-staining on the specimen.
cha-4 ($ 45.00)
Bashen Quarry, Waddamana, Tasmania, Australia
CHABAZITE specimen cha-5
$ 40.00
$ 40.00
Dims: 2.9" x 2.3" x 1.4" (7.3 x 5.8 x 3.6 cm)
Wt: 3.90 oz. (110.6 g)
Shimotokura, near Numazu, Shizuoka Prefecture, Japan
This small hand specimen consists of scores of tiny Chabazite crystals that rest on a slab of igneous host rock. The crystals do not exceed 0.2" (0.4 cm) along any axis but are in excellent condition, showing almost no human-induced damage. They have the classic rhombohedral form and pearly luster. Their color is a milky-white and they are all at least partly transparent, though most contain veil-like inclusions that give them their color. There is a thin, olive-green colored layer between the Chabazite and the base rock. This layer appears to be made up of small round clusters of tiny needle-like crystals- I cannot identify them, though they make me think of actinolite by their form or olivenite by their color.
cha-5 ($ 40.00)
Shimotokura, near Numazu, Shizuoka Prefecture, Japan
CHABAZITE specimen cha-6
$ 48.00
$ 48.00
Dims: 1.9 x 0.7 x 0.7" (4.8 x 1.8 x 1.8 cm)
Wt: 5.7 g
Bashen Quarry, Waddamanna, Tasmania, Australia
This small thumbnail specimen consists of a stalactitic formation that is completely covered with a layer of crystalline Chabazite. The crystals achieve a maximum diameter of 0.4" (1.1 cm) and are in excellent condition, showing no damage. All have very good trigonal tabular form with hexagonal outlines and possess well-defined edges and clean faces that show a pearly-to-vitreous luster. They are colorless and transparent, though their intense internal fracturing makes them appear essentially milky-white and translucent. The material that forms the core of the stalactite is milky-white in coloration and very crumbly. I do not know what it is made of.
cha-6 ($ 48.00)
Bashen Quarry, Waddamanna, Tasmania, Australia
CHABAZITE specimen cha-7
$ 63.00
$ 63.00
Dims: 2.5 x 1.8 x 1.4" (6.4 x 4.6 x 3.6 cm)
Wt: 2.6 oz. (73.2 g)
Bashen Quarry, Waddamanna, Tasmania, Australia
A crumbly, pale brown host rock acts as the base for two druses of intergrown Chabazite crystals. The crystals that make up the druses are generally in very good condition, as damage is mostly limited to the edges of each druse. Individual crystals achieve dimensions of 0.3 x 0.2" (8 x 5 mm) and show excellent six-sided trigonal tabular form, with well-defined edges and striated but clean faces that possess a bright pearly-to-vitreous luster. All are colorless, but appear to have a milky-white coloration and moderate to dim translucence to to intense internal fracturing. There are a few thin veins of Chabazite running through the host rock beneath each druse.
cha-7 ($ 63.00)
Bashen Quarry, Waddamanna, Tasmania, Australia