I remember bijou, from the list of French words that form plural by adding "x": bijou, caillou,chou, genou, hibou, jeujeu, pou. But I have never heard it mean anything but
"jewel".
"They were all displayed in that chamber of the Castle into which I had been first inducted, and which served, not only as the general sitting-room but as the kitchen too, if I might judge from a saucepan on the hob, and a brazen bijou over the fireplace designed for the suspension of a roasting-jack."

ijou
adj : small and elegant; "bijou villas"; "can Americans be
persuaded to pay out dollars for bijou cars?"
n : a small and delicately worked piece


Source: Webster's Revised Unabridged Dictionary (1913)

Bijou \Bi*jou"\, n.; pl. Bijoux. [F.; of uncertain origin.]
A trinket; a jewel; -- a word applied to anything small and
of elegant workmanship.