Mining of iron ore in the Franklin Mining District, NJ was attempted as early as the 1630s but was stymied as the zinc ores were confused for iron and confounded the smelters of the day.  Successful mining of iron then zinc was up and running by 1848, ending in 1986.  375 mineral species have been identified at Franklin and many of them are fluorescent.  Waste rock from the mines was used for fill material and concrete production at the mines and in the adjacent towns.  The waste rock contained fluorescent minerals and thus some of the concrete made from the waste rock glows under UV light.  In the concrete above, the red is calcite, CaCO3, and the green is willemite, Zn2SiO4.