Mata Ortiz Pottery. ARMANDO SILVERA - MONUMENTAL BLACK GLAZED OLLA WITH CARVED DECORATION. A very large coil built olla, 15 inches tall, 12 inches in diameter at its widest point. An imposing piece, strong in both the potting and the decoration. Signed by the artist on the bottom. This olla has a flattened base, allowing it to stand on its own without a supporting ring. In excellent condition, without scratches, chips or cracks.