Legolas had seemed wary, almost like some feral creature, before, and so even with his blessing Thranduil's movements were very smooth as he approached, and his hands hesitated for a moment as if for final confirmation before he finishes reaching up to touch it. The texture feels strange under his fingertips, and because he cannot see the clasp straight off, he feels for one. It's too small to have been slipped over his head, which means there must be a hinge and clasp somewhere. He'd break it if nothing else worked.