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What is your favorite mineral? Mine is a brave isometric mineral called Franklinite. Franklinite is in the spinel group with many other minerals that have a cubic or isometric crystal system. The spinel group, specifically the iron spinel group, is made up of minerals such as magnetite, which is commonly used in steel production, and zinc ferrite, which is used as a pigment. As the name of the subgroup, all minerals in the iron spinel group contain the element Fe or Iron. But unlike the other minerals, franklinite was the one that caught my attention the most.
The Franklinite was discovered in 1819 in Franklin, New Jersey and was named after the place where it was found and the inventor from the United States, Benjamin Franklin. Mentioned above, franklinite is a mineral from the iron spinel group and has an isometric crystal system. The mineral itself is a metamorphic rock and has a hardness of 5.5 to 6. Although the chemical formula for pure franklinite is (Zn, Fe2 +) (Fe3 +) 2O4, franklinite is generally found with manganese, which makes it the most recognizable formula: (Zn, Mn2 +, Fe2 +) (Fe3 +, Mn3 +) 2O4.
Here’s a fun fact: Franklinite used to be an important zinc mineral during the time the Franklin and Sterling Hill mines were open. The mines eventually closed, the use of Franklinite in zinc died and it no longer became a major mineral in zinc production. However, the mineral is still an important iron ore, which is why it is the reason for its name in the subgroup.
Color is the one that most attracts people’s attention. The color of Franklinite varies mainly from black to gray with frequent appearances of white. Although difficult to notice in some photos, the franklinite has streaks ranging from reddish brown to black and fragments that are known to be translucent. There are also times when different minerals intertwine with Franklinite. But in most cases, the mineral would be zinc, which looks red and stained.
You may be wondering why a muted mineral like franklinite caught my eye, but personally I find dark, metallic colors to be the most attractive to my eyes. It was not only the color, but also the octahedral shape of the mineral itself. I found the shape of the mineral and the fact that it fluoresces under UV light fascinating. Almost like granite or marble, the dark colors of the mineral show the rock strata and the patterns and lines that appear in the layers to make interesting contours and indentations. There are also times when the mineral looks like graphite and as if you could draw or write with it. All these facts make something that may seem boring at first glance interesting and aesthetically beautiful.