A thin layer of this beautiful cobalt carbonate species, deposited over a rounded knoll of calcite, makes for a showy specimen, 360-degrees around! Mostly you get plates, not nice knolls like this for a display collection in this size range. This particular style came out in the 1970s. Ex. Ed Ruggiero collection. I have seen only a few of them in many years, and this one is of high quality for color saturation and form I would say.