Ceramic coatings were part of Pictorico Papers descriptions. The following is a quote from Mitsubishi's website:
This is the first of its kind, an inkjet paper just like professional silver halide metallic photo papers. Pictorico’s patented and unique ceramic coating technology gives this metallic paper greater ink absorption which renders superior image reproduction. Colors are more brilliant and stunning, turning even ordinary prints into sought-after works of art.
This may be true or just fancy "coating speak".
Harmon FB Matt is a paper I'm familiar with. Bought a lot before it went the Ilford way. Its 300gsm, seems thinner than a 300 weight paper, but it's heavy and one of the smoothest of the matts. Came in Natural & Bright White.