We consider the question of how well points in a quadric hypersurface ${M\\subseteq\\mathbb{R}^d}$ can be approximated by rational ${\\mathbb{Q}^d\\cap M}$. This contrasts with more common setup approximating manifold all ${\\mathbb{Q}^d}$. provide complete answers to major questions Diophantine approximation this context. Of particular interest are impact real and ranks defining quadratic form...