Should I buy a diamond engagement ring or a gemstone one?

The question lands in my inbox about once a week, usually from someone who's just discovered a deep blue sapphire on Instagram and is now second-guessing the diamond their partner's mom has been lobbying for. I don't mind it. I'd rather the question gets asked before the deposit is down.

A diamond-natural or lab-grown-does one thing extremely well: it takes a beating. A 0.90 carat round brilliant in a six-prong 18k setting is going to look almost exactly the same in twenty years as it does the day you pick it up. Sapphire is a 9 on the Mohs scale, ruby's a 9, and that's genuinely close enough for a daily-wear ring, provided you're not grinding your knuckles into concrete. Emerald is where I start shaking my head. It's a 7.5 to 8, which isn't the problem-the problem is that nearly every emerald on the market is fracture-filled with oil or resin, and the moment that ring goes through a hot dishwasher cycle or a clumsy hour at the gym, the filler can sweat out and the stone looks cloudy. I've had three emerald engagement rings come back to my bench in the last five years for re-oiling. Two of them were barely eighteen months old.

So if you're leaning toward a colored stone, I'd steer you to sapphire or ruby first. A Ceylon sapphire in a medium cornflower blue or a pinkish-red Burma ruby (heated, not unheated-you do not need an unheated ruby for a ring that's going to share a bathroom with hairspray) will hold up. Spinels are another favorite of mine, a solid 8, and they tend to be cleaner than ruby at the same price point. But you should know that colored stones collect scratches that diamonds don't, and after five or six years of daily wear, the facet edges on a sapphire can start to look a little soft. That's not a tragedy. It can be repolished. But it's a reality I make sure clients hear.

Last February a woman named Julia came in with a cushion-cut mint tourmaline her fiancé had bought loose on Etsy. Beautiful stone. 3.02 carats, unheated, genuinely fine color. She wanted a solitaire. I asked if she was certain she'd be okay with a ring she couldn't wear to the climbing gym or the garden. She was adamant. We set it in a 2.2mm 18k rose gold bezel, which at least provides some protection, and I told her to take it off for anything more vigorous than typing. Twelve months later she was back-the stone had a 1.8mm chip on the girdle from a single unlucky knock against a metal stair railing. I recut the tourmaline down to 2.58 carats and rebuilt the bezel. She still loves it. But she said, quietly, that nobody had told her a colored stone was that much more fragile. I'm telling you now.

Diamonds carry their own baggage. The tradition is heavy. Some of my clients have to navigate strong family expectations that an engagement ring "should" be a diamond, and fighting that battle isn't always worth the emotional cost. If you love a sapphire but your grandmother will mention the diamond thing every Thanksgiving until she dies, you might pair a colored center with diamond side stones and call it done. Or you can ignore her. I've built enough rings for both kinds of people.

A moissanite is not a diamond, as I've said before, but if you're asking it's because someone already mentioned it. It's a 9.25 on the Mohs scale and it throws more rainbow fire than diamond. Some people adore that. Some people find it too disco. Try to see one in person before you commit.

Cost isn't the deciding factor it used to be, not with lab-grown diamonds cratering in price. You can get a 1.5 carat lab-grown round, G/VS1, for roughly the same budget as a fine unheated Ceylon sapphire of similar size. At that point the question is just which one you'd rather look at for the rest of your life.

I'd ask you to picture Tuesday morning. Not the proposal day. Not the honeymoon. A regular Tuesday, three years from now, when you're washing a coffee mug and the ring clinks against the ceramic edge. Which stone makes you feel like yourself when you glance down at your hand? Buy that one. Everything else-the durability math, the family pressure, the resale value speculation-is just scaffolding around that question.