A classic thumbnail specimen of the famous pieces of fowlerite (a zinc-bearing variety of rhodonite) from the Franklin Mine. It's important to note that fowlerite was at one time a valid species, mostly because fine crystals of rhodonite were almost completely unheard of prior to the discovery of the crystals from Franklin. Typically, fowlerite will have a slightly different color than the actual rhodonite crystals, with more of a brownish overtone as opposed to the saturated pink hue we're used to seeing from Franklin. This piece features a sharp, well-formed, 9 mm crystal of fowlerite sitting aesthetically on calcite matrix. The fowlerite crystal has a rough "contact termination" on the top, so it's not 100% complete, but it's still a very nice example of this hard to find classic material. The calcite shows a glowing red fluorescence under UV light. From the collection of Frank Keutsch. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Fowlerite
A zinc-bearing manganese pyroxenoid related to rhodonite — a pink mineral of the Franklin, New Jersey deposits.
Intro adapted from Wikipedia (CC BY-SA).
Fowlerite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Mn,Zn)SiO₃.
IMA symbol Fwl, IMA status: questionable, named in 1832.