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When you think of a 4 carat engagement ring, you might picture a celebrity red carpet moment: breathtaking sparkle, serious size and an equally serious price tag. And it’s true! Once upon a time, a 4 carat diamond ring would have been reserved for the likes of celebrities, royalty and the ultra-wealthy.
You might be surprised to learn that, thanks to the rise of lab grown diamonds, Moissanite and other lab grown gemstones, that level of luxury is no longer reserved for the very few. Today’s couples are discovering that a 4 carat engagement ring can be both ethically made and surprisingly within reach, offering incredible brilliance, presence and value.
Whether you’re drawn to a timeless solitaire or are considering creating a custom 4 carat ring, this guide explores what makes 4 carat engagement rings so captivating to modern couples, and why now is the perfect time to go bigger and bolder than you might have previously thought you could.
What does a 4 carat engagement ring look like?
A 4 carat engagement ring makes an unforgettable impression. It’s the kind of piece that catches the light (and everyone’s attention) the moment you walk into a room. But what does 4 caratsactually mean?
When we talk about carat, we’re actually referring to weight, not size. One carat = 0.2 grams. A 4 carat gemstone weighs 0.8g, regardless of whether it’s a diamond, Moissanite, ruby or sapphire.
While, generally speaking, the higher the carat weight the larger the gemstone tends to be, its visual size actually depends on its shape, cut and density. A 4 carat round brilliant and a 4 carat oval may appear different in spread, even though they weigh the same. Likewise, a 4 carat ruby will look smaller than a 4 carat diamond because it’s denser, meaning a smaller ruby will weigh the same as a slightly larger diamond.
What’s more, the quality of the cut has a major impact on how large a gemstone appears. A poorly cut diamond can carry extra weight deep within the stone or around the girdle, where it isn’t visible once the gem is set. This means you could pay for additional carat weight that doesn’t translate to extra sparkle or surface area. A well-cut diamond or Moissanite, on the other hand, will reflect light beautifully and look more impressive for its size. That’s why a diamond’s cut grade often matters just as much, if not more, than its carat weight.
At Moi Moi, we hold every gemstone to the highest standards. Our premium lab grown diamonds feature perfect Hearts and Arrowscuts or achieve Triple Excellentratings in cut, polish and symmetry — the highest grading possible. Our exclusive SUPERNOVA Moissanite is also precision-cut to maximise brilliance and fire, making it the world’s most brilliant gemstone. No matter the carat weight, every gemstone at Moi Moi Fine Jewellery is crafted to reveal its full beauty, ensuring exceptional sparkle from every angle.
4 Carat Lab Grown Diamonds vs 4 Carat SUPERNOVA Moissanite
Modern couples shopping for engagement rings are looking beyond mined diamonds, in search of options that are both ethical and exceptional in quality. At Moi Moi, our two signature gemstones, premium lab grown diamonds and SUPERNOVA Moissanite, each offer their own kind of brilliance.
4 Carat Lab Grown Diamond Rings
Lab grown diamonds have the same sparkle, strength and structure as mined diamonds. Even a highly trained expert can’t always tell the two apart! The only real difference between a mined diamond and a lab grown diamond is where it’s formed and how long it takes.
A mined diamond forms when carbon is exposed to extreme heat and pressure deep within the earth’s crust and mantle, a process that takes billions of years. A lab grown diamond forms in a very similar way, but inside a modern laboratory where the same conditions are carefully recreated. Using a tiny diamond seed, the crystal grows layer by layer over a few months instead of millennia. The result is identical in every way, just faster, traceable and far more sustainable and ethical.
Lab grown diamonds also offer incredible value. A 4 carat lab grown diamond is priced at just a fraction of what you’d pay for a comparable mined stone. That means you can enjoy the brilliance and presence of a larger diamond, without the inflated price tag and without compromising on quality.
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4 Carat SUPERNOVA Moissanite Rings
For those who want even greater brilliance and exceptional affordability, SUPERNOVA Moissanite is an outstanding alternative to diamonds. SUPERNOVA Moissanite is the world’s most brilliant gemstone, perfectly cut for maximum fire and light return, with none of the undesirable “rainbow” effect seen in earlier generations of the stone.
A 4 carat SUPERNOVA Moissanite offers extraordinary sparkle, durability (ranking 9.25 on the Mohs hardness scale) and size at a remarkably accessible price point. The difference in cost compared to a 4 carat diamond, even a lab grown one, is significant, allowing you to invest more in a larger centre stone, in your setting or even in wedding bands if you choose.
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So, Which Should You Choose?
Both Moi Moi premium lab grown diamonds and SUPERNOVA Moissanite offer stunning results. If you value the classic elegance of a diamond, traditional diamond composition and certified grading, a lab grown diamond might be for you.
If you love maximum sparkle, durability and incredible value, SUPERNOVA Moissanite delivers this and more at a fraction of the price of both mined and lab grown diamonds. Why is Moissanite cheaper than lab grown diamonds, you ask? Because they are two completely different gemstones; Moissanite is made from silicon carbide, which is less rare and easier to produce than the carbon required to make lab grown diamonds.
Either way, you’re choosing a ring that’s sustainably made, ethically sourced and expertly cut, qualities that define every Moi Moi engagement ring.
Choosing the Right Shape for a 4 Carat Engagement Ring
One of the most exciting parts of choosing or designing a 4 carat engagement ring is deciding on the shape of your centre stone. The right cut not only defines your ring’s style but also influences how large it appears and how it sparkles.
At 4 carats, every shape makes a statement. It’s just about finding the one that suits your hand and your aesthetic best.
Round Brilliant
The most timeless and universally loved cut, the humble round brilliant is favoured for its perfect symmetry and unmatched sparkle. A 4 carat round brilliant feels classically elegant and endlessly versatile. Its even proportions also mean it suits almost any setting style, from a simple solitaire to a detailed halo.
Oval
The oval cut is incredibly flattering on the finger, and its elongated shape gives the illusion of even greater size. A 4 carat oval ring is ideal if you want impressive coverage and sparkle without the bulkier look of some square shapes. Take a look at our Regan, Octavia and Viola 4 carat oval engagement rings for inspiration.
Emerald
The emerald cut is all about sophistication. Its hall-of-mirrors effect highlights clarity and clean lines rather than sparkle, giving a 4 carat emerald cut engagement ring an understated yet powerful presence. Our Mariah Emerald is a classic 4 carat emerald engagement ring, while our Zali ring offers a more modern take with its striking, gender-neutral east-west setting.
Radiant
If you love the step-cut shape of an emerald but want extra brilliance, the radiant cut delivers both. It combines crisp edges with a brilliant-cut facet pattern, giving a 4 carat radiant ring plenty of sparkle with a modern edge. Our Allegra and Josefa rings are two brilliant examples of 4 carat radiant rings.
Cushion
Soft and romantic, the cushion cut combines the square outline of a radiant with rounded corners for a vintage-inspired feel. Cushions are typically squarer in shape, however elongated cushions (like the one Taylor Swift received from Travis Kelce) can give the appearance of greater size and also gracefully elongate the finger, much like an oval or a radiant cut.
Pear
Elegant and eye-catching, the pear cut is a blend of round and marquise shapes. It gives the illusion of a longer finger and, at 4 carats, commands attention with its distinctive teardrop silhouette. Our Yulia ring is a stunning example of a 4 carat pear cut lab grown diamond ring.
No matter your preference, the centre stone shape you choose for your 4 carat engagement ring should reflect your personal style, whether that’s modern and bold or timeless and classic.
The Best Settings for 4 Carat Rings
In any engagement ring, 4 carat rings included, the right setting will enhance the centre stone’s brilliance. Certain setting types will even protect the centre stone from daily wear and tear and help it feel secure yet comfortable on the hand.
These are some of our preferred settings for 4 carat centre stones.
Solitaire
A solitaire setting is timeless for a reason. With minimal metal and maximum sparkle, it allows your 4 carat diamond or Moissanite to truly shine. A classic four or six-prong design keeps the stone secure while highlighting its natural shape and brilliance.
Halo
A halo setting surrounds your centre stone with a frame of smaller diamonds or gemstones, amplifying its sparkle and visual size. For some, a 4 carat gemstone may appear large enough on its own, while for others, a delicate halo adds extra dimension without overwhelming the design.
Hidden Halo
For those who prefer subtle detail, a hidden halo sits beneath the centre stone rather than around it. It adds a flash of sparkle from the side profile and gives your 4 carat ring an elevated, refined finish. It’s a hidden extra detail not everyone will know is there, but you will, which can make the ring feel that much more special.
Bezel
In a bezel setting, a fine rim of metal encircles the gemstone, creating a sleek, minimalist look while offering excellent protection. A bezel setting is a particularly great choice for those who lead active lifestyles or who work with their hands.
Three-Stone or Trilogy
If you love a ring with extra presence and meaning, a trilogy ring is a great choice. A trilogy ring features two side stones that accentuate the beauty of the centre stone, and together the three stones symbolise your past, present and future. Our Allegra Radiant trilogy ring is one of our best-sellers, featuring a 4 carat radiant cut centre stone flanked by two Cadillac side stones.
Cathedral
With elegant arches that elevate the gemstone above the band, the cathedral setting adds height and structure without distracting from the centrepiece. It’s an ideal choice when you want a 4 carat engagement ring with both presence and poise.
Find Your Dream 4 Carat Ring at Moi Moi Fine Jewellery
The rise of lab grown diamonds and gemstones has changed everything. They offer the same sparkle, durability and wow-factor as mined diamonds, but at a price that’s much more affordable for the average person and without the well-known environmental impacts or ethical concerns.
Because lab grown diamonds and gemstones, like SUPERNOVA Moissanite, offer such incredible value, you can enjoy the size and presence of a larger carat diamond at a fraction of the cost of mined stones. This means you can go bigger and bolder with your engagement ring than what you may have once thought was possible.
At Moi Moi Fine Jewellery, we’re proud to offer Australia’s largest collection of ready-to-wear lab grown diamond and SUPERNOVA Moissanite engagement rings. Our best-selling 100 Carat Collection contains a selection of beautiful 4 carat rings, which you can view and try on in-person at our Sydney and Melbourne flagship stores. Each ring is handcrafted with care and precision, using only premium lab grown gemstones, carefully selected for their exceptional qualities by our dedicated team.
Whether you find your dream 4 carat engagement ring among our ready-to-wear range or decide to custom design your own, our friendly team will guide you through every step.
