Alstonite, sphalerite, galena - Sun vein, Nenthead, Cumbria, England

 A classic, historic English specimen of rare alstonite on galena with sphalerite. Well-formed, classic, steeply pyramidal and bipyramidal alstonite crystals up to 8 mm in length. The alstonite crystals are in very good condition.
 This is a very beautiful, richly populated specimen of this extremely rare double carbonate of barium and calcium.