Generally, I don't think it is appropriate to take pictures of art in order to produce an interesting photograph. Because by doing this, the photographer is using someone else's creativity to say "Hey, look at this cool photo I took." The problem with that being that they didn't take a cool photo, they just took a photo of something that already looks cool, thereby using someone else's work for their benefit.
That being said, this picture is of a glass casting done by me and with lighting and positioning that I used to create an image that is something more than the original piece of art (the casting) being photographed. Since the casting is also my creation, I believe I can claim creative license for my creating this image using a prior work of art.
The casting itself is cast using sand to create a mold of a limestone carving (the carving had been loaned to me by the original artist for this purpose). The mold was then filled with molten glass and slowly cooled in an annealer.
