Fig. 2From: The quantification of physico-mechanical properties and durability of onyx-travertines from Santa Ana de los Ríos de Cuenca, EcuadorAccording to the lamination, onyx-travertine appearance has two main variations: parallel and normal to lamination. Photographs of typical observed surfaces of test specimens are presented: YT (a, b), PT (c, d), GT (e, f), WT (g, h). Parallel to the lamination: a, c, e, g; Normal to the lamination: b, d, f, hBack to article page