It’s important to find out what interests do you two have in common, so the gift will be something you’ll both like. If it’s true love, nothing really big is expected, something small and silly should do it. Of course you can buy something expensive if you have extra money, but it won’t affect your relationship much. Probably, depends on your commitment.
Now to the actual gifts. We’re talking about jewellery here. Rings, bracelets and necklaces.
Ever seen one of those necklaces which you can tear apart in two? Now that’s a good idea. Is it going to be a heart, a bird or whatever( something what both of you like ), each one of you has the other half. And that’s the point, you both have necklaces with one part of something, but you can put them together only when you are near each other, If you have one of those, it’s obvious that you are probably taken and are someone’s half, which might prevent flirting if they get it right. And, well, if that’s what you want.
Bracelets are useful since most of them is unisex, everybody loves wearing them. So, why don’t you buy two same ones, give one to your partner, and leave one for youself? Maybe get one with your partner’s name, and he/she does the same. You can talk about that, see what you like. Or a bracelet with some special quote. Quote which you two keep saying all the time, one of your favourite lyrics, or quote which can be found in a book which you both read and hold onto.
Rings are mostly referred to marriages and serious stuff, but if you get ring which is cool and awesome enough, marriage is the last thing coming to your partner’s mind. Of course you can get a ring for you two with some quote or special notch, but that will probably look too serious, and I suggest you to avoid that, unless you’re sure you’re building a commitment, or you’re already in the relationship for long enough. But if you’re not, you wanna do something cute and silly, based on your common interests.
If both of you are rock/punk/metal lovers, why not getting a jewellery containing those references? Music was just an example, but you get the point, and it’s valid for all types of jewellery, also for the other things.
Jewellery is good since it’s practical, easy to have around, and you both can talk about it to see what you like, and what you’re planning to buy for yourselves to remind you of one another.