sepallit
Sepallit is a fictional geological term that does not correspond to any known mineral, rock, or geological formation. There is no scientific literature or established definition for "sepallit." It is possible that "sepallit" is a misspelling of a real term, a neologism from a fictional work, or a fabrication.
If "sepallit" was intended to refer to a real geological concept, further clarification or context would be
The study of geology involves classifying and understanding the Earth's materials and processes. This includes identifying