Jewelry attractions in Vietnam

I am going to Vietnam on vacation shortly and will have a day to
spend in Hanoi before we meet up with the “tour group” for
backpacking and kayaking. Are there any jewelry related things I
should try to see, and are there any gemstones or supplies that would
be worthwhile/safe for a non-gemologist (who doesn’t speak
Vietnamese) to buy there? Thank you for any advice. Julia