If you're budget-restricted, you'll appreciate this Montblanc Pendant. It's a foolproof choice and a good investment. You might also want to take a look at this Kenzo Pendant. It's a product you'll love which also doesn't cost a fortune.
If you can afford to spend a little more, look no further than this Maison Margiela Pendant. This item doesn't cost too much, but absolutely deserves a spot in your wardrobe. Also take a look at this Valentino Pendant. It's an attractive option both price and quality-wise.