There are some wonderful images on Boston.com from photographer Olivier Grunewald who has captured the blue fire of burning sulphur at a volcano/mine in Indonesia. The full article presents some 30 images of the remarkable scene at Kawah Ijen.
[Olivier Grunwald photographs of the Kawah Ijen sulfur flames via Boston.Com]
I always like images like these, they make us question what things should look like or should be like and look at what they are actually like. This is a common issue in creating digital environments of characters and having to put what people expect rather than what would really be there...