I thought the same thing guys. But the joint is a little TOO smooth (IMHO) to be acrylics glued together. There's a nice blurring between the materials that I don't think you'd get in a glue-up. For example, if you look at Eagle or Ron's glue-ups, which are masterful, there is always a strong demarcation between the materials. So, if it isn't a glue-up acrylic, I want to know what it is!!! I thought it might be a form of ebony, perhaps with a lacquor finish, but I wanted to know for sure!
Upon closer examination, I really think I know what it is. First, Jim, I think you're right about the blurred demarkation lines. More about this in a second. Secondly, the lines between my glue-ups aren't all that strong (usually). It depends on the technique and glue being used. Now back to this pen. The brass color is from the brass tube... I'm nearly certain. Now notice the lines of demarkation. They bulge counter to the turned bulge of the barrel. Where the material is thicker, you see "less" tube. The material is a tinted resin or acrylic and there is just enough tint in it to give it a more opaque quality where it is thicker. 
Well, here I am. Sorry, but I was working on a pen and a pencil, not a set. I appreciate your interest and I wish I was good enough to do all the things that have potentially been attributed to me, but I'm not. Anthony is dead on. It's acrylic and I got it from CSUSA. It was in their last catalog, but was called "Blue Pearl."
Originally posted by alamocdc
<br />...The brass color is from the brass tube...The material is a tinted resin or acrylic and there is just enough tint in it to give it a more opaque quality where it is thicker...
Billy: I think you are on the right track; but slightly off in your interpretation. I looked at the picture in the CSUSA catalog and there is supposed to be a very distinct "pearl stripe"(for lack of a better word) in the blank. My guess is that we are seeing the brass tube through the "pearl" portion of the blank??
Maybe I can help. The CSUSA catalog and website do not agree on the name of this particular color. The catalog calls it "Blue Pearl" and the website calls it "Blue/Black/Horn." The color you're seeing isn't coming from the tube, it was there before I ever drilled it.
You definitely have to be careful drilling this for a Jr Gents/Baron or other larger pens. The blank is only 5/8". This is a giant hint to CSUSA - make these blanks 3/4". I had some anxious moments drilling it.
I had a similar occurance with a black and mother of pearl acrylic blank from HUT. As the material got thinner, the mother of pearl portion became translucent and took on the golden color of the tube underneath. It was stunning, but a bit of a surprise when expecting the milky white of mother of pearl.
Regardless, a beautiful pen and a masterful example of the craft.