If you're jewelry shopping, there are lots of shops to choose in the Kowloon side such as in Nathan Road, Mong Kok, and Tsim Sha Tsui. However, Hong Kong is most famous for its Jade Market in Yau Ma Tei. Of course, always be cautious when shopping here. There are some stalls selling fake merchandise. 

If you don't know how to scrutinize fake or real jewelry, it's best just to shop online from a known jewelry retailer. Of course, if you're shopping for a magnetic bracelet, you can't go wrong whether you shop for it in a jewelry market or online. But the advantage of shopping in an online store like billythethree, is that they have a large selection of jewelry and you don't have to worry about picpockets when shopping online. The site makes shopping for jewelry fun plus they ship worldwide. 

Anyways, whether you're shopping for magnetic bracelets or silver jewelry, be it in Hong Kong or online, never forget to compare.