Polymer clayers use mica powders more often than metallic waxes for various reasons, but either can be used as well as many other colorants (the most commonly used brand of mica powder is "Pearl Ex").
When the powders are used, they are most often used for "highlighting" just the upper areas of any dimensional area or item, or for "complete coverage" of the upper and lower areas.
When acrylic paints are used, they're most often used for "antiquing" which is coloring only the lower areas and/or crevices of an item (the paint is rubbed all over, then wiped off of the top areas before it can dry). That can give an "aged" look but it also just gives a lot of dimension as "shadowing."Warning though
... once you start playing around with mica powders in particular, you'll probably go crazy with all the things it can do and how much bang for the buck it can give!
There are several pages at my site that deal with antiquing, highlighting, completely covering, and staining, but the best place to start is probably the Molds page (just because I happened to have written most there then never moved it):http://glassattic.com/polymer/molds.htm
> Antiquing, Highlighting, Staining
(It's also covered on the Stamping and Texturing pages, as well as the Powders and Paints pages.)
Since you mentioned glazes and "triple thick" glaze, you might want to check out my message in this previous post about the various kinds of clear finishes that can (and shouldn't, if you didn't know) be used directly on polymer clay when that's desired:http://www.craftster.org/forum/index.php?topic=190875.msg2005953#msg2005953
(and this one is shorter with some other info, and more recent:http://www.craftster.org/forum/index.php?topic=273974.msg3096293#msg3096293
I think one of those also has a link to the page at my site on Finishes for more details.
Of course, no sealer is ever necessary
on polymer clay like it is on air-dry clays and many very experienced clayers never use a liquid finish unless they need to hold something on or in certain other circumstances (though a lot of the clayers who mostly do miniatures like "charms," etc, like to high-gloss most everything).
If those clayers ever want a high gloss look, they'll usually instead wet-sand then electric buff the baked clay item which can bring the clay itself up to a high-gloss shine...or they'll just take the surface up to a beautiful "sheen" with hand buffing (or shorter electric buffing), or may alternate polyurethane with sanding and buffing.
(There's more about "sanding and buffing" in my answers here, if you're interested:http://www.craftster.org/forum/index.php?topic=198978.msg2111968#msg2111968http://www.craftster.org/forum/index.php?topic=165503.msg1685352#msg1685352
Oh, and there's info on doing all kinds of "eyes" on this page:http://www.glassattic.com/polymer/sculpting_body_and_tools.htm
And dragons (heads, bodies, skin, eyes, teeth, etc) are covered on that page too, under Scales & Dragonskin, etc, and a few other cateogies... and also on the main sculpting page, under the Websites category (the ones that are still active anyway):http://glassattic.com/polymer/sculpture.htm
And here are loads more dragon eyes and dinosaur eyes, etc, courtesy of Google:http://www.google.com/images?q=dragon+eye+polymer+clayhttp://www.google.com/search?q=dragon+eye+polymer+clayhttp://www.google.com/images?q=dragon+dinosaur+eye+polymer+clayhttp://www.google.com/images?q=polymer+clay+eye
Have fun, and report back!
P.S. If you have more questions in the future, the best place to ask them is in the other polymer clay sub-board Discussions & Questions
so they're sure to be noticed:http://www.craftster.org/forum/index.php?board=239.0