You don’t always see the metallic particles. Sometimes they are big, visible flakes and sometimes they are really tiny and instead of seeing the flakes you just see the effect of having them in there. Automotive paint colors are a complicated science. Sometimes there are metallic flakes in the color coat. Sometimes there are reflective elements added to the clear coat. Different colors will look different based on the primer coat applied underneath. To really learn it, you would need to talk to the manufacturers or maybe some really experienced and trained automotive paint experts.
I work in the paint shop in a BMW manufacturing plant. Some of the colors we paint are really cool. At one time, we had 5 or 6 different metallic black colors. They would just look a beautiful shiny black until the angle of the light changes. Then you would see a red or gold or deep blue start to show up. Carbon black is the blue one and it’s absolutely beautiful. Our mineral white is a plain white color coat with mica flakes in a top coat. It looks like you can reach into the depth of the paint.