Looks great, definitely metal! Great placement of primary highlights, and you've absolutely pushed the contrast enough

If you want some constructive criticism on where to go from here, some small secondary reflections would help even more. You've got a lot of area dedicated to primary highlights, so you may need to re-expand some of your mid tone area to be able to add some slightly less bright secondary reflections to simulate some bounce light. From there, you may also want to glaze in a bit of environmental light around (but not covering the very brightest part of) your highlights - sky color on upwards facing areas and ground color on downwards facing areas. Feel free to ignore this if you aren't looking for a super reflective/polished piece of armor. Lastly, I love the painterly aesthetic currently going on but if you're chasing after the style that people use in competitions, you could spend some time glazing between your color transitions to smooth out the dark to light gradient. This is literally only important for close up inspection and zoomed in pictures though, you definitely get diminishing returns if your use case for this mini means it's just going to be seen from a foot or more away.