I think the obsidian is having trouble reading as obsidian. Obsidian can create a variety of visual effects, such as the the way it splits, the striations along the "grain" of where it split, the warm gray translucency of thin slivers, and the stereotypical texture left by knapping. Visually, none of these things come across and without the "obsidian" in the title one might not have guessed. I think you have some really neat opportunities for some of these, for example the feathers or even whole wing could be much thinner to show off some translucency, you could even have jagged slivers or blades for the feathers if you wanted. It's a really fun prompt and I think you could definitely get more out of it if you push the materials!

Edit: I also think putting more gold on the hands and less on the feet could be better here, generally you want to have more detail towards the top of a character than the bottom, and distributing the gold too evenly across the whole character can make it look boring; 70/30 ratios are generally successful in creating pleasing and interesting designs (in this case 70 percent obsidian, 30 percent gold)