inartificialness

His color is, in its sphere and to its purpose, as perfect as human work may be: wrought to radiance beyond that of the ruby and opal, its inartificialness prevents it from arresting the attention it is intended only to direct; were it composed with more science it would become vulgar from the loss of its unconsciousness; if richer, it must have parted with its purity, if deeper, with its joyfulness, if more subdued, with its sincerity.

On the Old Road Vol. 1 (of 2) A Collection of Miscellaneous Essays and Articles on Art and Literature John Ruskin 1859