Unusual Handel Table lamp?

I have a Handel table lamp with handpainted glass which is signed and numbered. I have not seen similar glass on internet and my question is if it is unusal and who could have painted it. The glass looks very icy but I think it should be so as it has chipped ice finish. Somebody told me to try to take away the " frost " but I think it should remain as it is. The base is like a tree and is also signed "HANDEL".