Ceramography of stabilized zirconia is a difficult task, often requiring hot etching [1]. In previous work we developed a technique of mechanically weakening the grain boundaries by ultrasonic machining and then etching at room temperature [2]. Reports on pure (unstabilized) zirconia show that microstructures could be attained even without etching [3]. The major difference between the stabilized and unstabilized forms of zirconia is the presence of the tetragonal (t) phase in the former and its absence in the latter. The fact that unstabilized zirconia does not need etching means that the monoclinic (m) phase of zirconia does not need etching. Similarly, the fact that stabilized zirconia is difficult to etch simply means that t-phase is not easily etched. However, etching is based totally on differences in the chemical composition of the surface [4]. Accordingly, an etchant that is capable of etching zirconia should be able to do so irrespective of the physical structure of the zirconia, i.e. irrespective of whether it is in m-phase or t-phase. Therefore, the difficulty of etching zirconia samples containing t-phase particles needs explanation. In order to assess the etching behaviour of the different phases of zirconia, two samples were chosen: sample A with 33.9% t-phase (the remainder being m-phase) and sample B with 100% t-phase. Both samples were prepared from 12 tool % ceria-stabilized zirconia (TOSOH, TZ-12CE), by dry pressing with a suitable binder and sintering. Sample A was sintered at 1600 °C for 2 h, furnacecooled and subsequently heat-treated at 400 °C for 2 h. Sample B was sintered at 1350 °C for 2 h and air-quenched (i.e. removed from the furnace soon after the soaking time was over and allowed to cool in still air). These sintering schedules were selected from previous experiences [5] of tailoring the phase structure in 12 mol % ceria-stabilized zirconia. Normally, surfaces are polished before etching. However, in zirconia there are numerous reports on the t-to-m phase transformation arising due to various stress inducing environments such as machine grinding [6-8], electron-beam heating during transmission electron microscopy observation [9] and even indentation [10]. In particular, 12 mol % ceria-stabilized zirconia is highly transformable and t-to-m phase transformation in this material has been reported even due to polishing [11]. Since polishing would induce t-to-m phase transformation,