PHILLIPSITE
Specimen phi-3

Dims: 2.7" x 2.2" x 1.9"(6.9 x 5.6 x 4.8 cm)

Wt: 4.20 oz.(119.0 g)

Dough Boys Mine, Tasmania, Australia

This is one of the more intriguing zeolite specimens that I have seen. It consists of a crust made up of round clusters of Phillipsite crystals that have a maximum diameter of about 0.4"(1.0 cm) and rise about 0.2"(5 mm) up from their base. Some of the clusters on the specimen's edge are broken, so that one can see a strange trait. Even though the clusters show large, shiny terminations on their surfaces, their cross-sections show round, acicular formations that contain countless radiating, needle-like crystals; these crystals have diameters that are much too small to warrant the size of those terminations. There are two very large(8 mm x 3-5 mm x 2 mm) crystals amidst the clusters. These large crystals are colorless and transparent, whereas the clusters are colored white and are translucent, but all have a vitreous luster on their terminations. The radial material inside the clusters, however, has a silky luster, likely due to the density of the crystals' arrangement. All of the mineral rests on a bed of basalt. This is the first specimen I have seen of this mineral; I believe that it isn't a very common zeolite.

Dims: 1.6" x 1.5" x 0.9"(4.1 x 3.8 x 2.3 cm)

Wt: 28.1 g

Dough Boys Mine, Tasmania, Australia

This Phillipsite specimen consists of a crust made up of several white, rounded, intergrown clusters of crystals. The largest of these clusters measures 0.5"(1.3 cm) in dimeter and rises about 0.2"(5 mm) out of the base rock. Some of the clusters on the edge of the specimen are broken, revealing their cross-sections; these cross-sections show the acicular, radiating habits of these crystals. Unlike another specimen that I have seen, these thin crystals seem to have terminations that are proportionate to their thicknesses. There are a few larger, stubby crystals that average about 0.1-0.2"(3-5 mm)in diameter and are colorless and transparent, whereas the round white clusters are translucent. All have a vitreous luster and good form, with very little damage, except for the clusters on the specimen's edge, of course. The crust that this material has formed rests on a base of basalt that contains many loose, round nodules which are paler and more green in color than their matrix. There are also a few rounded, transparent nodules made up either of a different zeolite or, more likely, quartz.

Dims: 3.1 x 2.6 x 1.7" (7.9 x 6.6 x 4.3 cm)

Wt: 5.35 oz. (151.6 g)

Horseshoe Dam, Maricopa County, Arizona, U.S.A.

Scores of tiny Phillipsite crystals rest in vugs in the igneous host rock of this speciemen. They are extremely small, not exceeding 0.1" (3 mm) along any axis, and are in excellent condition, due to the protection provided by the hollows in which they rest. They are difficult to study even with a 10-power loupe, but appear to occur either in tiny, rounded compact sprays or as druses of tiny crystals. The more exposed rounded sprays have a cream coloration, whereas the druses have a much cleaner white color. The dull brown host rock on which they rest is very rough and heavily pitted with hollows, most of which contain Phillipsite.