Its title could be a bit more modern, but A Girl’s Guide to Buying Diamonds is perfect for stashing in your purse, and it’s about as practical and comprehensive a guide as a befuddled ring-buyer could ask for. Author Randi Molofsky gets the “four Cs” (cut, clarity, carat, and color) out of the way early on with lots of helpful diagrams and photos before moving on to cleaning tips, style recommendations for different personality types (“the tomboy,” “the romantic,” “the rock star”), advice for buying online, and ways to ensure that the diamonds you’re considering are conflict-free. She also includes a replica of an actual grading report and a helpful interactive checklist to aid in comparison shopping. So, while purchasing a diamond may never be wholly stress-free, all of the above will be a great balm for jittery nerves when you’re finally ready to buy the ring of your dreams.