Virtually all kaleidoscopes have an "eye piece" on one of the ends of the 'scope for the viewer to look through. (On occasion you will see a 'scope without one, but the problem of dust in the mirrors and the impact on the view tend to make this not very attractive.)
The eye piece is normally ordinary glass, often with a slightly convex surface. These will be most commonly found in simpler, less-expensive 'scopes.
Some artists who desire special effects and/or are crafting higher-end 'scopes, will use various designs of optical lens with different features to achieve those magnifying effects. These lens can be as elaborate/special as the artist desires.
The bulk of the kaleidoscopes that I craft -- the mini kaleidoscopes -- have plain glass eye pieces with a slightly convex surface. This is a choice based on the impact on the "view" and the effect on the cost of the 'scope. On occasion I have crafted higher-end 'scopes with optical lens to achieve a special effect.
As far as I know, all kaleidoscopes require a “tube” (the most commonly used term, although not always an accurate one, since tube implies “round” and many kaleidoscopes are not “round”, but other geometric shapes and/or patterns) to hold the mirrors (an essential ingredient of a ‘scope). I suppose, in theory, one could find a way to hold the mirrors together without inserting them in a “tube” of some kind, but I would think it would be difficult to hold them together in such a way that the mirrors could not be damaged or come loose. So, for our purposes, we shall assume that kaleidoscopes have a “tube” or holder for the mirrors composed of some material.
The three most common materials used, as far as I have been able to observe, are wood, stained glass, and polymer clay. I work with wood for my ‘scopes and have posted many examples earlier. (A quick search of the web will result in quite of list of artists making kaleidoscopes in wood, one way or the other.) There are any number of artists who work with stained glass in a variety of configurations for their “tube” or holder. (See the earlier post of the artistry of Frank Higgins in stained glass.) There are also quite a number of artists who use polymer clay or ceramics in one form or another for their holder. (See the earlier post with samples of Jacqui Smith’s artistry.)
A variety of other materials are used by some artists including metal (in some cases including precious metals such as silver), paper/cardboard, plastic, acrylic, etc. In fact, most any form of a container that will accommodate the mirrors can be used as a holder – e.g. my limited edition of cigar box kaleidoscopes posted earlier.
So, as you explore the fascinating world of kaleidoscopes look for the wide variety of materials and shapes used by various artists for the “tube”/holder of their ‘scopes. You will be amazed and delighted.
My latest posting -- a mini kaleidoscope in Hawaiian Koa.
Another medium that is very popular for kaleidoscopes is polymer clay used in a variety of ways for the scope body (tube). To my mind one of the most unusual and highly creative artisans of this medium is Jacqui Smith. She studied at the Philadelphia College of Art, and became a noted illustrator of children's books, as well as a designer of a large variety of figurines, dolls and jewelry collections, including work for the Franklin Mint.
During a sabbatical from her commercial work, she found the world of kaleidoscopes and now develops one-of-a-kind, high-end, gallery-quality, and custom kaleidoscopes. Because they are so labor-intensive, she normally only creates 10 to 12 kaleidoscopes a year.
To my mind, truly works of art to be treasured by anyone lucky enough to have one. In addition to be a true artisan, Jacqui stands ready to help other kaleidoscope artists in a variety of ways through her involvement in several kaleidoscope artists groups.
Posted this morning a kaleidoscope crafted in Kauri wood from New Zealand. Kauri wood is believed to be 50,000+ years old. Apparently ancient forests sank into bogs and lay underwater for eons and only recently are being recovered. There is a strong effort to preserve these ancient logs for use by woodturners and carvers the world over. Really quite beautiful wood and a joy to work with.
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.