Siderite ps. after calcite - North Cape Prov., South Africa
 
 Pseudomorphosis (perimorphosis) siderite after calcite. The shape of the calcite is clearly visible. The siderite has a good luster, which gives the piece a velvety shimmer. Although the siderite is only about 1 mm thick, the piece is stable and well intact. A curious rarity with a beautiful aesthetic