Weight, either in baht or in grams, has nothing to do with purity. Inquire about the percentage of gold content or carats before making a decision. Ask the shopkeeper to weigh the piece for you so that you can be sure of the exact weight before buying . Intricately designed pieces are more expensive than simply designed ones. While the goldsmith's charge is sometimes negotiable, the gold price itself is not.
Some large shop offer a certificate or warranty with each gold purchase.
If you wish to sell or exchange a piece of gold jewelry, do so at the shop where you bought it. Usually, you will get a better price and an assurance of quality. Selling gold to a pawn shop is not a good idea, as these shops generally give you only 70 to 85 percent of the actual value of the piece. If you want to test the purity of a gold pieces, contact the Department of Science Service at Tel. The charge for testing is Bt500 per piece, and the process takes one week.