Glaucodot twin, 2.5 cm, from Håkansboda, Westmanland, Sweden. (4) Pyrargyrite, 2.9 cm, from St. Andreasberg...beryl, 2.4 cm, from Slieve Corra, Mourne Mountains, County Down, Ireland. Gem-crystal thumbnails illustrated...single crystals, (3) thumbnails from one state, county or foreign country, and (4) thumbnail element groups...Eagle’s Nest mine, Michigan Bluff District, Placer County, California. Jingnan Zhang collection and photo...calcite, 3.1 cm, from the Kearsarge mine, Houghton County, Michigan. Ralph Clark collection, ex Minette collection; |