SUSSEXITE on FRANKLINITE, SUSSEX COUNTY FRANKLIN MINING DISTRICT UK (cabinet)

Sussexite is an extremely rare manganese borate mineral with the chemical formula MnBO2(OH). It commonly forms monoclinic prismatic crystals that are often fibrous in nature. The mineral exhibits colors ranging from white to pink and yellowish white, displaying a pearly luster. With a Mohs hardness of 3 and a specific gravity of 3.12, it is relatively soft and dense. The mineral is named after the Franklin Mining District located in Sussex County, New Jersey, where it was first identified in 1868.

Franklinite is an oxide mineral that is part of the iron (Fe) series within the normal spinel subgroup, characterized by the chemical formula Zn2+Fe23+O4.