Franklinite, named for Benjamin Franklin, is found in Franklin and Sterling Hill, Sussex County, New Jersey. It is black in color and a slightly magnetic member of the spinel group.
Willemite is a rare nesosilicate and zinc mineral found principally in Franklin, New Jersey with Franklinite and Zincite. Willemite can have a variety of colors from white, colorless, reddish, green, yellow, orange and black. It is known for its brilliant green fluorescence.
Calcite is a Carbonate mineral that is most widely distributed on the Earth’s surface. It is a common constituent of sedimentary rocks with Limestone in particular. A Calcite formation can take on many different shapes and sizes which is dependent on the location, ground water occurrence and temperature. Calcite is usually white or colorless but can be gray, red, yellow, green, blue, violet, brown or black. The deeper the color is usually indicative of the definitive impurities from the earth or water.