Just a couple of images to illustrate the explanation given by Sue. I haven't altered the colours on the images, this is how it shows up. You can just spot the iridescent effect at the top.
The vase fits the philosophy of the artist perfectly, well for me at least, when he says that beauty can be found in colours and simplicity of form and shape.
Having said that, even though I like the vase very much, it is still a pain in the neck to take pictures of.