For most, the choice of engagement ring stone is a simple one. You get a diamond – and ideally one that’s large, well-cut, and with excellent clarity. But what if you’d like to break from tradition? After all, your relationship has unique qualities that set it apart from everyone else’s. So why shouldn’t you go for an engagement ring that’s going to set you apart from the rest of the world?

Let’s take a look at a few of the more uncommon stones, and assess their advantages.

Amethyst

This purple variety of quartz tends to be cheaper than the equivalent diamond. It lends itself extremely well to cushion and larger oval cuts. The intensity of the colour tends to correlate with the value of the stone; a more vivid purple tends to point to a higher concentration of iron. The best amethyst gems are ‘Deep Russian’, which is a sort of deep purple with a little bit of blue and red.

Stones of this kind can be discoloured over time by detergents and other caustic substances, which is why they should be handled with care.

Emerald

Green stones tend to contrast extremely well with gold engagement bands, such that they appear even greener in context. All emeralds are green, by definition – they’re a subcategory of beryl, which contains chromium or vanadium. If you see something advertised as ‘red emerald’, then be cautious, since this is a marketing term.

The emerald has been credited with mystical healing properties since the time of the ancient Egyptians, and it’s likely to be valued long into the future, too. Look for an emerald that’s brilliant and clear. Emerald gems, naturally, are suited to emerald cuts – though there are alternatives available.

Sapphire

Princess Diana, and then later Kate Middleton, were presented with sapphire engagement rings, and thus there’s a little bit of royal tradition surrounding this particular stone. It’s literally fit for a princess. Sapphires come in a range of shades, from pinks to deep blues – but it’s the latter that’s come to be associated with sapphire in general. The most common size for sapphires is around 6mm, which is equivalent to a three-quarter-carat diamond.

Opal

Opals have the advantage of uniqueness – no two opals are quite alike, with each incorporating a slightly different combination of hues. They’re made from tiny silica spheres. If the spheres are uniform in shape and size, then you’ll get the distinctive ‘precious’ opal, which contrasts with the ‘common’ opal. The former represent just 5% of the total opals out there.

These stones are distinctive, and have an almost mythical look to them. They’re more fragile than diamonds and other stones, however, and thus they shouldn’t be worn in settings where they’re likely to be bashed around.