by Firkin - uploaded on February 3, 2016, 9:08 pm
I called this an amethyst frame for obvious reasons - it looks like raw unpolished amethyst. But it's nothing of the kind. It started out life as a picture of a tree in silhouette against the blue sky (from Pixabay). I distorted it heavily in Paint.net to give superimposed shapes with rotational symmetry of order 16. This gave the appearance of crystals around the outside. I chopped the uninteresting inner bit and adjusted the hue to give the violet of amethyst. Then it was vectorized in Vector Magic.