There are several current varieties of grayish/blue limestone, all from the same general region of Portugal: the Mira de Aire and Candeeiros Range in the West of Portugal (the Azul Cascais limestone reserves nearby Lisbon are virtually depleted or inaccessible due to urban sprawl). Those varieties are: Vidraço Ataíja Azul: Very hard compact limestone, finely … Continue reading AZUL – Blue-gray ornamental limestone varieties from Portugal