A 3D realistic depiction of a crystalline skull crafted from transparent sapphire-like material, with soft azure luminescence radiating from within, casting intricate light patterns. The piece floats ethereally against a deep, void-like black backdrop, rendered meticulously with Octane's high-fidelity capabilities to accentuate its captivating, otherworldly and futuristic aura. Subtle iridescent highlights dance across the surface, adding a layer of enigmatic allure.