Monday Mineral: Apophyllite

I have mentioned "Siletzia" and the Siletz River Volcanics a couple of times before, toward the end of this post, and poetically in this one. If you flick over to the second link you can see a picture of a nice pile of pillow basalts overlain by a nice set of columnar jointing. Pillow basalts are the result of basalt erupting or flowing into water; as a result they are severely fractured, and full of glass and void spaces. Basaltic glass is quite unstable as rock material goes, and it decomposes fairly quickly to palagonite. In the alteration process lots of ions move into solution and reprecipitate in a very predictable suite of minerals, particularly zeolites and calcite. Another common mineral in this suite is apophyllite. While zeolites are hydrated tectosilicates, and calcite is calcium carbonate, apophyllite is a phyllosilicate, like the mica group.
The above picture doesn't show the apophyllite too well (the most identifiable mineral here is natrolite, which I'll address another time), but it does show the palagonitic base on which the crystals have grown. While I have seen lots and lots of this in quarries in the hills north and west of Corvallis, I think this particular sample came out of parking lot gravel. It pays to look at what you're walking on.
The two above pictures were taken from slightly different positions, and below I've cropped them and placed them side by side to create a cross-eyed stereopair. I can definitely see this pop out, but I'd sure appreciate some feedback from geology types to let me know if this works for you as well, and perhaps more importantly, if it helps you visualize the geometry of this mineral.
Frequently the apophyllite is too small to readily identify useful features without a binocular microscope, but if you have some good-sized crystals, it has some very distinctive features that make it unmistakeable.

It is in the tetragonal symmetry group, so the basic form of the mineral is a four-sided prism with two pinacoids terminating the c-axis. The prism faces have a glassy luster, and are almost always striated. In the picture below you can see a prism face with striations. As an interesting aside, you can see that the apophyllite has grown around the needles of natrolite, which tells you the natrolite precipitated first. This is cropped from the second picture above, just above the left edge of the penny.
The pinacoid, on the other hand, shows a pearly luster, and is not striated. The following four pictures were taken from slightly different angles to show the pearly luster as the the pinacoid is illuminated from different angles.

The other feature that does not show up on this sample is that frequently the corners between the pinacoid and two prism faces are beveled, sort like a roof. Those faces have a glassy luster and are unstriated. I do have a sample that shows this well, but I can't quite seem to get it to show up in photos; it's too glassy and transparent. The crystals pictured here are milky enough that they are distinct from one another in photographs. Nevertheless, in my experience, the beveled corners are more the rule than the exception. Yet another characteristic is a perfect cleavage parallel to the pinacoid. As an open question, I almost typed "obviously, since it's a phyllosilicate," and realized that I've always assumed that all phyllosilicates have perfect cleavage across the c-axis. I guess that seems logical, but I guess I don't really know that it's so. Is my assumption accurate?