Norbergite is one of several rare yet collectable minerals from the Franklin mines in Franklin, New Jersey. Norbergite fluoresces tan to yellow color in subjected to shortwave UV light. Norbergite was first discovered in Norberg, Sweden from where it gets it name. It forms as small grains in the marbles of contact metamorphic environments. Its commonly associated with franklinite, fluorite, and calcite.The most significant feature of Norbergite is that it is of the Humite group. Humite group members have a mixture of  silicate and oxide layers.