I can't help you with the rock type, but could you tell me about the vinegar test? (How to do it, when, what to look for etc.) thanks!
I wonder if your rock is marble or has some quartz? I have no idea though.
75 Gallon Freshwater•Tetras, Pleco, Platys, Cory's, Danios, and Marble Hatchets• 4 Baby Platy Fry in breeder box•