My lovely inlaws have given me a budget of £250, which I would be willing to add probably about another £100 to for something lovely, that is classic, and beautiful. This piece is to be handed down to my newborn dd on her 16th birthday, but I've to wear it until that point.
She was born at the very end of December, on a Saturday (so that birth month stone/birth day stone can be taken into account, potentially - birth month stone is taken as ruby or turquoise, and birth day as diamond, according to wiki).
I personally wear mostly platinum and white gold/silver, but for special pieces I do have some yellow gold (an Alex Monroe necklace DH got me for Christmas that makes reference to DD's middle name - thankfully she looked like the name we'd picked! And a ring from my grandmother).
I'm not fussed on what the jewellry is, ie, necklace, earrings etc - I want to steer clear of a ring, though, as she looks like she'll have lovely, skinny fingers, and mine are sausage like.