The dirt, rust, texture on the rollers is very rough at the microscopic level. They leave a multitude of scratches on the surface even when rollers appear super clean and smooth. (seen in the first pic I posted.) There do appear to be a few different patterns on the surface that different rollers can make but all the patterns are scratches. IItlooks like the inside of the wrinkles have few(er) scratches leading me to believe they are not made by mechanical force but something else like uneven cooling. Studying these surfaces has let me see how the so called "exotics" have the exact same surface patterns as CAC slags which give me even more assurance that they are genuine. Here is a pic of a new contemporary 5/8" marble. Sure easy to see the difference from hand and machine made at this level of magnification. I need to put a few of your mibs under the scope to see what their surface looks like!