>>116033415There are about 50 pearls on that necklace. Pearls go for 300 to 1500 dollars. Let's lowball it and say these are worth 500 each. That's $25,000 in his hand if he sells the gems individually.
For him to have pulled this off though, he had to have known she'd be standing there and wearing that pearl necklace, meaning he needs to know about the necklace, meaning it needs to be not just any pearl necklace, but a famous one, which means its value is probably ten times that or more.
Of course, stealing art is the easy part. Criminals are always caught in the trying to sell it part.