I think it's a very beautiful thought that you want to give your girlfriend a nice present, and that's why I also hate to say that you have to be very care careful about how much you pay and especially where you are buying your gold.

Unfortunately Bangkok has a bad reputation about gem and gold scams - and not without a reason. You will probably meet a lot of 'friendly' Thai people who want to 'help' you find just 'the right' shop. So make sure you are buying at a serious serving gold shop.

The unit of gold weight in Thailand is measured in Baht just like the Thai money, but in this case it only refers to the gold weight. You may want to buy a 1 Baht gold bracelet which is a nice piece. The gold price in Thailand is at the moment about 15,000 (money) Baht for 1 (gold) Baht. But with the current inflation in Thailand the price may be changing.

I'm not saying all this to scare you, I really hope you will find a nice present for your girlfriend. But to be prepared do take a look at this link to see how the gem and gold scams are working:

2Bangkok.com - The Gem Scam