Deep in the hills of New Jersey lie two of the world’s most unusual mines: Sterling Hill and nearby Franklin. A greater variety of minerals has been found here than at any other deposit, and 35 of Sterling’s minerals aren’t found anywhere else. The mines were a major source of zinc from the 1880s until they closed—Franklin mine in 1954, Sterling Hill mine in 1986.

Visible Light

Minerals That Glow in the Dark
When certain materials are exposed to invisible ultraviolet light, they give off visible light. Franklin-Sterling Hill, New Jersey, is the fluorescent mineral capital of the world. Over 70 kinds of minerals from this location fluoresce, creating a riot of color under ultraviolet light.

Ultraviolet Light