Hematite Nodule, Fe2O3 Iron oxide. with Siderite and Quartz. This specimen was found on my final visit to Marine colliery waste heaps. Hoping to find some Millerite, I arrived to find that the waste heaps had been landscaped out of existence. As I was despondently leaving the remaining tiny car park, I spotted this nodule by the entrance, which did at least give me something to show for my 136 mile round trip. The centre of the nodule is lined with tiny platey Siderite crystals, with two small crystals of Quartz.