I don't know what the material difference is in the two sockets but I have used the two different sockets for the last 50 years. Now I am talking about top quality snap-on sockets. I have found when you use a chrome socket in a impact it just stretches it out of shape and you can tell it was used as such making it have a short life. When you use a impact socket (black) on a long breaker bar it will break a lot faster then a chrome socket. So I have learned through years of hard use chrome sockets for hand wrenches and black impact sockets for impact wrenches for a long socket life. And yes I will exchange the two yet in a pinch. I am also talking about 6 point sockets in both types.