Cassiterite, arsenopyrite on muscovite – Minas da Panasqueira, Covilha, Castelo Branco, Portugal
 
Magnificent paragenesis of cassiterite and arsenopyrite on muscovite. The crystals are in flawless condition and convince with beautifully defined crystal shapes and a particularly good luster.  The arsenopyrite is double terminated.
An all around wonderful collection specimen from the famous site in Portugal.