Green hyalite

Photograph by Alan Rice.

Photography contest, Winner.

Hyalite glowing green, or fluorescing, under ultraviolet light (ultraviolet C 100–280 nm). The photographer writes, "Hyalite is a form of opal with a glassy and clear appearance. My brother builds ultraviolet lights for mineral exploration and is silhouetted by the abundant hyalite. This sample is deep underground in a tungsten mine in Nevada, USA."