“Ruby in Fuschite,” a mineral rock from India, photographed under natural and long-wave UV Light (photos courtesy of John Rofrano)
By shinning an ultraviolet long, medium, or short-wave light on a mineral rock that fluoresces, we too can see what birds naturally do when they look at the rock. It is the ultraviolet reflecting off of the streaks of certain minerals in the rock that cause this phenomenon that we see.
How do we know birds can see fluorescent minerals?
“Some creatures can see forms of light that we cannot. There are plenty that can see ultraviolet, which is light with a wavelength of between 100 and 400 nanometers. We can find out whether an animal can see light of a particular wavelength by testing whether that light will travel through the lens of its eye. The lenses of healthy humans block ultraviolet light, so we cannot see it. But for other species, seeing ultraviolet can make it easier to see in dim light,” Ron Douglas of City University London in the UK.