The coefficient of friction of Filled Germanys Ettringer Trachyte tiles can vary depending on several factors such as surface finish, texture, and any additional treatments applied to the tiles. As a specific value was not mentioned, it is difficult to provide an exact coefficient of friction for this specific type of tiles.

To determine the coefficient of friction, it is recommended to consult the manufacturer or supplier of the tiles, as they may have conducted tests to determine the slip resistance or friction properties of their products. They may be able to provide you with the relevant information or test results.