5. While hiking on the shoreline of an ancient, inland ocean, you find an interesting mineral (see pichae below). It has a non-metallic vitreous luster, andyoucansee three distinct cleavage angles. You

cannot scratch it with your fingernail, but you can scratch it with a copper penny. You put a drop of HCl on its surface, and you see a reaction. What is the name of this mineral? How did it form?