Vote for your favorite mineral in #MinCup26! - Sphalerite vs. Anorthite Both zinc ore Sphalerite and calcium plagioclase feldspar Anorthite have perfect cleavage that will split cleanly if you hit them with a hammer, but only one can claim a larger split of your votes!
Bridges et al. (2011): "Some early excellent linarite specimens are attributed to Roughton Gill Mine, but Davidson and Thomson (1951) expressed doubts about the provenance, an opinion supported by Bridges et al. (2008) who used mineralogical and geochemical evidence to support the view that these specimens actually originated from Red Gill Mine. In this study linarite is a fairly rare mineral; most specimens taking the form of a thin blue crust and are clearly a dump alteration product of galena and chalcopyrite. Crystals, when found, take the form of royal blue blades up to a maximum of 3 mm long."
Roughton Gill Mine, Roughton Gill, Caldbeck, Allerdale, Cumbria, England, UK