Caillois's opening words in The Writing of Stones provide a portal through which to enter this virtual gallery.
"Just as men have always sought after precious stones, so they have always prized curious ones, those that catch the attention through some anomaly of form, some suggestive oddity of color or pattern. Stones possess a kind of gravitas, something ultimate and unchanging, something that will never perish or else has already done so. They act through an intrinsic, infallible, immediate beauty, answerable to no one, necessarily perfect yet excluding the idea of perfection in order to exclude approximation, error, and excess. This spontaneous beauty thus precedes and goes beyond the actual notion of beauty, of which it is at once the promise and the foundation" (The Writing of Stones, 1-2).