Excellent crystal specimen of Siderite on Quartz from a well regarded location for Siderite specimens at the Tincroft Mine, Illogan, Cornwall. Crystals of Siderite are seen forming inter grown clusters measuring to 3cm, in a cavity rich Quartz-Hematite veinstone, very characteristic of the mine. Crystals of Siderite are translucent honey yellow to a rich brown, some crystals have internal orange reflections. A great Siderite specimen from Tincroft Mine.