The NEA Clay Club has been gathering the key geoscientific characteristics of the various argillaceous formations that are – or have been – studied in NEA member countries in the context of radioactive waste disposal, resulting in the publication of the Clay Club Catalogue of Characteristics of Argillaceous Rocks in 2005. This publication builds upon the 2005 NEA report by providing updated datasets for a select number of argillaceous formations presented in the previous report, as well as an expanded discussion of: the formations and their properties; the nuclear waste management organisations responsible for the implementation of the deep geological repository concept; the design concept proposed for a deep geological repository in the respective countries and rock formations; and some of the favourable properties of said argillaceous formations. A key goal of this report is to present the data in a manner that allows reasonable comparability (in both scale and methods) of the included parameters, in order to support the formal assessment and demonstration of the capacity of clay-rich formations to securely contain and isolate nuclear waste from the natural environment