Tuffeau stone — in French, simply tuffeau or tufeau — is a local limestone of the Loire Valley of France. It is characterized as a chalky or sandy, fine-grained limestone, white to yellowish-cream in appearance, and micaceous (containing some white flakes of mica, or muscovite). The soft stone is extracted from numerous quarries and has made a major mark on the architectural landscape of the Loire and its tributaries — especially the valley's world-famous chateaux.