After 40+ years of making pottery I finally have a perfect functional, durable gunmetal black. It has an incredible silky surface. It does not cutlery mark. It does not craze on anything. It is easy to clean. This is G2934Y with 6% Mason 6600 black stain firing using the PLC6DS schedule. I had to tune it a bit, adding about 15% glossy G2926B, because it was a little too matte on initial firings. But now it is perfect. These are heavy mugs made using the M340 casting recipe (and the casting-jiggering process). The speckled mug was made by casting a thin layer of the speckled version of the slip first, then filling the mold with the regular slip. I used a 40-minute cast to get walls nice and thick!
This is G2934Y satin matte with Mason 6600 black stain. The piece on the left was fired using a slow-cool firing schedule (C6DHSC). The schedule for the one on the right turned the kiln off at 2100F (after a half hour drop-from-2200F-and-hold), then it free-fell. The slow cool gives the glaze on the left time to crystallize, thus it is now a stony matte (rather than a satin matte). It is interesting that to this mix of the glaze I added 20% glossy clear, yet it still matted on the slow cool.
A type of ceramic glaze: Pebbly matte black. For functional surfaces, it has enough glossy to not cutlery mark and be easy to clean.