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!
Green et al. (2008): "The specimen in the Kingsbury collection at the NHM is described by Cooper and Stanley (1990) and comprises radiating sprays and crystal sections to 20 mm with leadhillite. In common with the Brae Fell specimens, it is almost certainly a fragment of an old specimen from the Leadhills-Wanlockhead district in Scotland. It is amazingly large, a single isolated example, strongly resembles Leadhills specimens and is unlike anything ever collected by anyone else at Roughton Gill."
