I've seen lots of them in bazaars and markets, and in stores in the city, and the prices are reasonable, but where are all these made (silver jewelry and beads, for example)? In some region of Thailand or in China?

I have heard that they actually make the gold chains they sell in Chinatown,Yaraphat rd.But it's only here say .I just had A gold bullet made from someone in Korat.

There is an Industrial Estate by the airport... It's called Gemopolis

http://www.gemopolis.com/

Most of the cheap jewelry you see on the streets, bazaars, and market are made in China.

Some are hand made by the sellers themselves.