This is a beautiful stamp souvenir sheet, issued by Comoros Islands in 2010, displaying minerals. Featured on the sheet are Stilbite-Ca, Tourmaline crystal silicate mineral, Liddicoatite crystal, Apophyllite-KF (Fluorapophyllite), and the tecto-silicate mineral Thomsonite of the zeolite group. The sheet is Post Office fresh, mint never hinged, and F/VF.