Thank you I lol at that first explanation.

He asks if the boarding school was Swiss because rich people sent their daughters to boarding school in Switzerland.
"You can't tell me nothin' if you ain't had an 8-track." -Sinbad

Then he throws the key into the air on purpose
I thought he threw the key out of some sort of shock that Nikki screamed and ran towards him.
Made you look

I don't think the Jeweller belived Nikki was Loudon's sister.She was'nt really bothered about convincing him,anyway.
Sadly,he was just a device to get the key away from Madonna's charachter.
He was funny,though!

The guy can tell just by looking at her,that she is trouble and not a high class wealthy person. So he purposly is rude to her by pretending to want to fix the broken clasp-I think he also saw her steal the cigerette holder that was displayed on the counter(the one she takes while he is taking out the necklace she wants to look at)That's why he throws her necklace/clasp in the air.He fans himself because he's a snob. About when he says "Is the school Swiss?" he's being snobishly sarcastic because of the way she is dressed-Swiss women used to wear those really short skirts. He knows she is from the streets and he's one of those people who thinks he's better than someone poor like her.
Oh,and the guy was also offended by Nikki when she is admiring the fancy necklace and asks Louden,"Do you think this will fit on a tiger?" Remember Nikki was pretending to be Louden's wife and you could tell that Louden was embarassed to be seen with her-the guy probably knew that Nikki was not his wife because Louden is one of their regular customers.
Anyway,I love this movie!