Arguably the most important part of a kaleidoscope is the "object center" -- that is, what it is that one "views" through the eye piece and the mirror configuration.
There are a variety of "object centers" -- oil cell, oil wand, tumble cell, tumble (image wheel), fixed image wheel, etc. I suppose, theoretically, most anything can be "viewed" depending on the design and construction of the kaleidoscope. The ones just mentioned are the most common.
Although all types have their adherents, my personal favorite is a tumble cell or tumble wheel (image wheel). To me, the beauty of them is that you never see the same image twice as the materials inside are constantly tumbling and re-arranging themselves. In addition, you get motion as well as changing images.
One can use a wide variety of materials in a tumble cell/wheel -- fragments of rocks and minerals, gemstones, beads, colored glass, colored plastic, glass ampules with liquid filling which then tumble in the cell, shells, bits of metal, etc. Then, just to make it more interesting, some artists "mix and match" materials to achieve the desired "view". One can even use sand. I designed and crafted a 'scope for a customer in Australia one time that used sand from her favorite beach along with some shell fragments she had collected. It was certainly a unique "view".
Picture of an image wheel kaleidoscope I crafted from reclaimed New Zealand Kauri wood and posted on my web store www.wrightmade.com. (See that site for information on the Kauri wood.)
One type of non-toy kaleidoscope that is not seen very often is one where the tube/body is made of paper or cardboard. (I am excluding the vast body of toy, party-favor, kaleidoscopes so popular for children's birthday parties, etc., which are usually paper/cardboard.)
On occasion, one will see a cardboard kaleidoscope that has been painted, or decorated in some fashion or other. I think some of them are really quite beautiful. I have no experience with how well they hold up from normal wear & tear, however.
Their tubes are designed to be used for polymer clay, painting, beading, whatever, and the component parts are of good quality. Below are some examples from their web site of finished 'scopes using several techniques for finishing the cardboard tube.
(Example of a tube with micro beads)
(Another example, this one using an oil wand.)
(This simple teleidoscope -- a variant on a kaleidoscope -- uses plain wrapping paper to decorate the body.)
As is true with kaleidoscopes in general, there are many variations available for both the artisan and the collector in 'scopes using paper/cardboard as the base of the tube.
Professional woodworker specializing in small-scale wood turning on a lathe. I work primarily with exotic woods from around the world and "Dymondwood" a laminated wood product that is dyed a variety of colors and provides a visually appealing end-product. Most of my turning is of kaleidoscopes, desk accessories, cutlery, back scratchers, key rings, etc. I market on the web and wholesale and consignment.