Post written as a reply to this question:
http://forum.corona-renderer.com/index.php/topic,576.0/topicseen.htmlHere's a quick but effective (I hope so) setup:
1. Create new CoronaMtl
2. In "reflection" slot assign CoronaColorMapper
3. In CoronaColorMapper a Gradient control pop-up window will appear, chose a colour gradient you wish.
4. In "input map" slot assign a standard Falloff map (optionally change mixing curve).
5. Adjust material's glossiness, reflectivity, etc.
I'm attaching the scene file if you want to experiment with my gradient. ;)