Generate a 3D model of a partially embedded organic fossil within a rocky cavity. The fossil should resemble a long-extinct creature with segmented limbs, hardened carapace, and remnants of soft tissue calcified over time. The structure should be twisted and incomplete, with erosion marks, mineral encrustations, and sediment layers. Surround the fossil with a detailed cave wall featuring stalactites, moss patches, and moisture streaks. The lighting should suggest a low, natural glow from bioluminescent minerals nearby. Use muted tones: stone gray, fossil beige, and hints of oxidized green. The model should evoke mystery and ancient biology, with clean topology suitable for scene integration or 3D printing