Ettringite with Calcite

A choice and highly aesthetic specimen with two hexagonal, acidic lemon-yellow Ettringite crystals to 1.7 and 1.8 cm long, perched either end of a well crystallised group of Calcite crystals.  Ettringite is a hydrous calcium aluminium sulphate and the crystals on this miniature grade from translucent outer shells with a glassy to satin lustre, to inner, opaque pale lemon-white cores.  The slightly longer crystal is not terminated whereas the smaller has one well terminated end.  A classic Ettringite from the N'Chwaning mines at Kuruman in the Kalahari Manganese Field of Northern Cape Province, South Africa.