Why We Don't Sell Sapphire Engagement Rings (and When You Should Buy One)

Sapphire is a magnificent gemstone. It is genuinely hard, genuinely historic, and genuinely beautiful, and if you want one, you should buy one. We do not sell sapphire engagement rings, and the reason is narrower than you might expect: a coloured stone absorbs the light a diamond returns, so it will never sparkle the way most people picture an engagement ring sparkling. That is a preference, not a flaw. Here is the honest case for and against, so you can decide which camp you are in.

In this article

• Why sapphire feels so romantic
• The honest case for sapphire
• The case against sapphire for daily wear
• Sapphire vs diamond at a glance
• Who should buy a sapphire ring?
• Why we do not sell them
• FAQ

Why sapphire feels so romantic

One ring created this entire market. In 1981, Lady Diana Spencer chose a 12 carat oval Ceylon sapphire encircled by 14 diamonds, set in 18 carat white gold, from the Garrard catalogue. It broke with royal tradition twice over: it was not custom made, and anyone with the money could have bought the identical ring. She picked it anyway, reportedly because it matched her eyes.

In 2010, Prince William proposed to Catherine with the same ring. Two generations, one stone, and a design that jewellers have been reinterpreting for forty years. If you find yourself drawn to a sapphire engagement ring, that ring is almost certainly why. It is a wonderful story and we are not going to talk you out of loving it.

The honest case for sapphire

It is genuinely durable. Sapphire is corundum, 9 on the Mohs scale. That is harder than almost everything it will meet in daily life, and far harder than the emeralds, opals and pearls that jewellers sometimes talk people into. A sapphire engagement ring is a practical choice, not a fragile one.

The colour is extraordinary. A fine Ceylon sapphire has a depth of blue that no colourless stone can offer. If what moves you is colour rather than fire, sapphire wins outright, and no diamond will ever satisfy you.

It is distinctive. Walk into a room of engagement rings and the sapphire is the one people ask about. For some couples that is exactly the point.

It carries meaning. Sapphires have signified wisdom, nobility and fidelity for centuries. If a blue stone means something to your family, that meaning is real and it matters more than any gemmological argument below.

The case against sapphire for daily wear

It does not sparkle like a diamond, and it cannot. This is physics, not opinion. A diamond has a refractive index of 2.42 and returns light as white brilliance and fire. Sapphire sits around 1.76 to 1.77, and because it is coloured, it absorbs a large share of the light entering it rather than throwing it back. A sapphire glows. A diamond sparkles. If you are picturing the flash across a dinner table, a sapphire will not give you that.

Hardness 9 is not hardness 10. The Mohs scale is not linear. A diamond is meaningfully harder than a sapphire, and only a diamond scratches a diamond. Over decades of daily wear, a sapphire's facet edges will soften slightly sooner. It is a small difference, but an engagement ring is the one piece of jewellery that never comes off.

There is no universal grading standard. Diamonds have the 4Cs, and an IGI or GIA report tells you precisely what you are buying. Sapphire quality is judged largely by eye, and terms like "royal blue" and "cornflower" are descriptive rather than defined. Two sapphires at the same price can differ enormously, and most buyers have no way to tell. That opacity is not in your favour.

Most sapphires are heat treated. Routine, disclosed, and accepted throughout the trade, but it means the stone you are buying has usually been improved in a furnace. Untreated stones of fine colour command steep premiums, and not every seller is candid about which you are getting.

Sapphire vs diamond at a glance

	Sapphire	Lab grown diamond
Mineral	Corundum	Pure carbon
Hardness (Mohs)	9	10
Refractive index	1.76 to 1.77	2.42
How it handles light	Absorbs much of it; glows with colour	Returns it; white brilliance and fire
Grading standard	No universal system	IGI / GIA, the 4Cs
Treatment	Usually heat treated	Growth method stated on the certificate
Best for	People who want colour and character	People who want brilliance and certainty

Who should buy a sapphire ring?

Buy the sapphire if colour is what you love, if the blue carries family meaning, if you want a ring nobody else has, or if you simply looked at Diana's ring and felt something. Those are all good reasons and none of them is a compromise.

Buy a diamond if what you picture when you imagine an engagement ring is the flash of white light, if you want a certificate that tells you exactly what you own, and if you want the hardest stone there is on the one piece of jewellery you will never take off.

There is no wrong answer here. There is only the question of which of those two things you actually want, and a lot of jewellers would rather sell you either than help you work it out.

Why we do not sell them

Not Mined exists to do one thing properly: hand-picked, IGI or GIA certified lab grown diamonds at D colour, VVS+ clarity and Ideal cut, set in 18ct hallmarked gold. Every stone we sell is graded on a standard you can check, and chosen for how it performs in light.

Sapphire is a different craft, judged by different criteria, and the honest thing is to say we are not the right people for it rather than add a category we cannot claim to lead in. If a sapphire is what you want, buy one from a coloured stone specialist who lives and breathes them.

If what you want is the sparkle, we can help. Our guide to moissanite vs lab grown diamonds makes a similar argument about the other stone we do not sell.

Frequently asked questions

Are sapphires good for engagement rings?

Yes, if you want colour. At 9 on the Mohs scale a sapphire is hard enough for daily wear, and it will not chip or cloud easily. What it will not do is sparkle like a diamond, because a coloured stone absorbs much of the light that enters it rather than returning it as white brilliance.

Do sapphires scratch easily?

No. Sapphire is corundum at 9 on the Mohs scale, harder than almost anything it will encounter day to day. Only a diamond, or another sapphire, can scratch it. Over decades of constant wear, facet edges can soften slightly sooner than a diamond's would.

Why did Princess Diana choose a sapphire?

She selected the 12 carat oval Ceylon sapphire from Garrard's catalogue in 1981, reportedly because it matched her eyes. It broke royal tradition because it was not custom made: anyone who could afford it could buy the same ring. Prince William later proposed to Catherine with it in 2010.

Are sapphires cheaper than diamonds?

Usually, for a comparable size, though fine untreated sapphires of top colour can be extremely expensive. The bigger difference is certainty: a diamond's 4Cs are graded to a published standard, while sapphire quality is judged largely by eye, so it is harder to know whether you have paid a fair price.

Are most sapphires treated?

Yes. Heat treatment to improve colour and clarity is routine and accepted throughout the trade, and reputable sellers disclose it. Untreated stones of fine colour command significant premiums, so always ask. Talk it through with us →