Home > Type Localities II – August 5 > MS1613 McGuinnessite

McGuinnessite - Sold


McGuinnessite is a copper magnesium carbonate mineral, specifically a member of the rosasite group. Erd et al. (1981) named the species in honor of mineral dealer and amateur mineralogist Al McGuinness (1926-1990), who discovered the mineral.

McGuinnessite forms a robin's egg blue coating on a rock fragment. Some radiating structure is visible oin places. Rich specimen! The matrix consists of serpentine, which supplied the magnesium to form the mcguinnessite. Rather rich example. This specimen was part of the Charles Trantham (1936-2020) estate. A handwritten label from Al McGuinness (the mineral's namesake) and a CT Minerals label accompany this specimen.