Without going too deeply into the scientific technicalities of cinnabar/vermilion properties, the differences between the two pigments are: cinnabar is created by the combination of mercury and sulfur through a natural process and found in mines in many locations, and vermilion is made by combining mercury and sulfur in very hot temperatures by alchemy.
Both have been used in art, cave and wall paintings, illuminations, body painting, cosmetics and such for many centuries. Pliny the Elder, Theophilus, and many others recorded the historical importance of both pigments.
Like the mythological basilisk story related in my previous blog entry, there is another very colorful legend I found delightful. Daniel Caspar von Lohenstein describes in his novel Arminius that during a monumental battle between an elephant and a dragon, "cinnabar is the mixture of dragon's blood and elephant's blood when they fight each other."
Victoria Finlay, in her book on color states, "but one of (JMW) Turner’s favorite reds may well have been cinnabar-which he used in its manufactured form, vermilion, and which Pliny described as the result of an epic struggle by and elephant and a dragon. These two troublemakers were always fighting, Pliny recounted and the battle eventually ended with the dragon-evidently rather a snaky one-wrapping its coils around its heavy enemy. But as the elephant fell it crushed the dragon with its weight and they both died. The merging of the blood made cinnabar." Apparently this is a metaphor for the combining of the heavy mercury and burning sulfur.
Again, you just never know where a little research into a subject is going to lead.
Margret, this is a wonderful story! I have never heard of the story of cinnabar. I’m going to tweet about this and hope to send some people over here. More artists need to be reading your blog.