For glass with a completely unique obscurity, consider glue chipping.

Glue Chipping is a very old art form used frequently around the turn of the last century. Basically a special glue is applied to the surface of clear glass causing the surface to chip away in unique, fern-like or frost-like designs. No two pieces will ever be the same. The process is hand-done, and due to a variety of variables, results are dramatic, not predictable, and always fascinating.

Glass can be chipped over the entire surface of the glass or it can be contained within a prescribed area for creative results.