Thai silver same as 925 sterling silver?
General idea of Thai silver is also known as 925 sterling silver, however that's not completely correct, Thai silver is also the definition of a workmanship, a traditional way to make silver items, and it could be 925 (92.5% silver + 7.5% copper) or 950 (95% of silver) or 999 (99.9% of silver). These can all known as Thai silver, as long as there were from that region and with that particular workmanship.
999 Fine silver is the best for jewelry making?
No, be straight, 99.9% is not as good as you think, the reason people don't like to use purely silver or we call 99.9% silver is because it's too easy to tarnish and too soft for jewelry making. Therefore most of the silver jewelry you see is made with 925 silver. it's simply because of utility.
BALI - THAI - HILL TRIBE - SILVER
Most of the jewelry or beads that fall under this category are made by the ethnic peoples of Bali, Thailand etc. and describes a "style" of jewelry design. People of these regions typically use either .925 silver or fine silver. Still, look for the silver mark or word.