Reply To: What minerals form the brachiopod geode crystals? Homepage › Forums › What Is It? › What minerals form the brachiopod geode crystals? › Reply To: What minerals form the brachiopod geode crystals? December 9, 2016 at 6:18 pm #16464 William HowatParticipant The first one looks kind of like calcite to me… …and the others look like Quartz, maybe with some Limonite (Iron Oxide)
