errr, in the retail game that's called a mark-up.gf once brought a gold chain for $300,went back next day a another merchant offered her $100
or you're a wood duck
my bet is you're a woody
On a side note:
If you wanna learn about Gems then you should head to Kao Sarn Rd, Bangkok and take up an offer from a tuk-tuk maniac and his $1 tour of Bangkok..
If you have your head screwed on then sit back and enjoy the free booze on offer from "the gem dealers"..
and enjoy handing over $1 to Mr Tuk Tuk at the end of the day when you promise you will return tomorrow with lots of $$$ to buy his friends/families gems
God i love Thailand.