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): "Rosasite was first reported in the British Isles by Kingsbury and Hartley (1957), who described several occurrences in the Lake District, mainly in the Caldbeck Fells and including Roughton Gill Mine. Although rosasite is widespread, usually in small amounts in British orefields, it is very common at Roughton Gill and it is surprising the mineral was overlooked for as long as it was. The Kingsbury Collection contains a group of small specimens of rosasite from the 60-fathom dumps. Collected in 1950, the rosasite is associated with hemimorphite; the specimens are typical of the site and there is no reason to doubt the validity of the Kingsbury and Hartley report. On the 90-fathom dumps, it occurs as small (up to 1 mm) blue-green hemispheres perched as individuals on other minerals, particularly hemimorphite, but commonly the hemispheres aggregate to form continuous botryoidal crusts which can cover areas up to 20 cm2."
Roughton Gill Mine, Roughton Gill, Caldbeck, Allerdale, Cumbria, England, UK