I think the problems are that
- the rock is so dark that the form doesn't read because the lit parts are nearly as dark as the shadows, especially since the bright ore makes the colours look even darker by comparison
- the ore is specks rather than readable shapes. It's fine to have some single-pixel highlights, but I think it'll read better if you have some chunkier shapes in there. Give the veins some structure.
Here's an edit that tries to improve your ore without straying too far from what you've for so far: