Roughly the size of a rather large pebble, the oyster is more gnarled in appearance, less uniform in color, and brilliantly whitish. It is a world categorically closed in upon itself. And yet it can be opened: that takes gripping it in a folded rag, plying a nickel and dull-edged knife, chipping away at it over and over. Probing fingers get cut on it, nails get broken. It's a rough job. The pounding you give it scars the envelope with white rings, a sort of halo.-- from The Nature of Things by Francis Ponge, translated by Lee Fahnestock
Within, one finds a world of possibilities for food and drink: beneath a mother-of pearl firmament (strictly speaking), the skies above settle in on the skies below, leaving only a rock-pool, a viscous green sack that ebbs and flows before the eyes and nose, fringed with a border of darkish lace.
On rare occasion the perfect formula pearls up in its nacreous throat, and we take it at once for our adornment.