Hello from a newbie to the forum. I have a collection of cast iron skillets that I use daily for cooking and I'm looking to add to my collection with different size skillets. There are these cast iron skillets at the antique store the patina looks like a pewter color not the classic black patina I'm use to seeing. Can you all tell me about why these skillets might look as they do and if it affects the the temperature and/or quality of cooking with these skillets.