A good representative piece of white to yellow microcrystalline Hinsdalite coating the surface of the rock veinstone.  Frongoch Mine was noted in the nineteenth century for large brown Pyromorphite crystals, but also renewed interest in the site was shown in the 1980's-1990's when a large range of rare Pb-Cu-Zn secondary minerals were found.  It was only quite recently that Hinsdalite and Corkite were noted to be present.