A new variety of mineral, which shines brightly under ultraviolet rays, has been discovered in the northernmost Japanese prefecture of Hokkaido.
A group of researchers, including those from the Sagami Chemical Research Institute, near Tokyo, and Osaka University, made the discovery.
The new find is a kind of organic mineral consisting of elements such as carbon and hydrogen that are found in living organisms. The mineral is light yellow under natural light, but it emits bright yellow or yellow-green light under ultraviolet rays.
The researchers say one piece of the mineral was contained in opal they obtained in a forest in Shikaoi Town and another was in a rock found in Aibetsu Town by an amateur mineralogist.
The group's detailed analysis revealed that the mineral is a new type made up of material called "benzopyrene." Very small amounts of it exist in petroleum.
The International Mineralogical Association registered the mineral in January under the scientific name "hokkaidoite."
Hokkaidoite is supposed to have been generated after remnants of living organisms under the ground were heated by volcanoes. The group says the new find could shed light on the mechanism of oil generation.
The institute's chief researcher, Tanaka Ryoji, says he wants people to know there are many more interesting minerals in Japan's mountains.
The mineral is to be put on display at the visitor center of Tokachi Shikaoi Geopark from Monday.