I just bought a set of ceramic front brake pads for a 2000 RX300 vehicle at my local AutoZone store. The pads look like not much different from the semi-metalic ones, with small copper particles mixed in the braking material. I was under the impression that ceramic brake pads would not have metal particles in the mix. Am I wrong?

The ceramic pads I purchased has the code DG-707 (for Duralast Gold). The next leg up is the model DG Cmax. I compared them at the store. The only difference I can see between the two is the cut glove, for which it is straight in the middle for the DG-707, and diagnal on the DG Cmax. Both are ceramic, but have copper particles in the braking material mix.