In "The Necklace," which describes the reaction of Mathilde and her husband when they realize that the necklace is missing?

They felt panicked at first, when they realized that it was no longer on Mathilde's neck and anguished later on, when they couldn't find it.

Explanation:

As a wealthy friend of Mathilde; Madame Foriester, had lend her a very precious jewel for her to go to that Ministry party, Mathilde never realized she had lost the necklace, until she was getting undressed to go to bed, so the first reaction of panick came out. She claimed she had it with her during the whole party, and her husband claimed there was no way she could've dropped it when running out of the place to get a cab, as he would've heard if the jewel had dropped. Both of them search for it anxiously during days.

They are shocked and panicked.