Hunger’s End by Robert Cheetham (New Worlds #171, March 1967) sees Caroline listening to Jimmy at a party. He says that physical beauty is valueless as it contributes nothing to functionality; she disagrees and, deciding that he doesn’t know what he is talking about, eventually dismisses him. As Caroline hands her glass to him so that he can get her another champagne, she notices a minute chip in it and deliberately drops it to the floor where it smashes.
The rest of the story alternates between Caroline’s adulterous affair with another man called David, who was at the party with his wife, and a sponge-like alien life-form that has been feeding on the seabed for aeons. The alien sponge is later harvested and put on sale, during which period it starts to starve. Caroline buys it (“huge, ovoid, delicately violet”).
The final scene (spoiler) has Caroline discussing her relationship with David on the phone before she goes to have a bath. She dreamily slips her finger into a hole in the sponge, and the alien bites it off. The story close with this:
“Then there’s the transiency of beauty,” said Jimmy. “Symmetry exists only so long as the apposite dimensional planes are exactly complimentary. Alter one side, change its shape by one iota, and symmetry, beauty, perfection, value—everything is gone.” p. 126
I’m not convinced by the point the story is trying to make, or that it would stop Caroline attracting David, but I suppose it is a short and effective enough piece.
** (Average). 1,700 words. Story link.