400ct Round Brilliant Cut Diamond

Find the exact 400ct round brilliant cut diamond you’re shopping for in the variety available on 1stDibs. Every item for sale was constructed with extraordinary care, often using gold, white gold and 18k gold. Find an antique version now, or shop for 3 vintage or 13 modern creation for a more contemporary example of these cherished accessories. You’re likely to find the perfect 400ct round brilliant cut diamond among the distinctive items we have available, which includes versions made as long ago as the 20th Century as well as those produced as recently as the 21st Century. There have been many well-made iterations of the classic 400ct round brilliant cut diamond over the years, but those made by Cartier, Oshi Jewels and Tiffany & Co. are often thought to be among the most beautiful. See these pages for a round cut iteration of this accessory, while there are also brilliant cut cut and cushion cut cut versions available here, too. When shopping for a 400ct round brilliant cut diamond, you’ll find that there are less available pieces for unisex or men today than there are for women.

The price for a 400ct round brilliant cut diamond starts at $410 and tops out at $16,888 with these rings, on average, selling for $3,560.

Antique diamond rings, diamond tiaras and dazzling vintage diamond earrings are on the wish lists of every lover of fine jewelry. And diamonds and diamond jewelry are primarily associated with storybook engagements and red-carpet grand entrances — indeed, this ultra-cherished gemstone has a dramatic history on its hands.

From “A Diamond Is Forever” to “Diamonds Are a Girl’s Best Friend,” pop culture has ingrained in our minds that diamonds are the most desired, the most lasting and the most valuable gemstone. But what makes the diamond so special? Each stone — whether it’s rubies, sapphires or another stone — is unique and important in its own right. April babies might claim diamonds for themselves, but just about everyone wants this kind of sparkle in their lives!

There are several factors that set diamonds apart from other stones, and these points are important to our gem education.

Diamonds are minerals. They are made up of almost entirely of carbon (carbon comprises 99.95 percent; the remainder consists of various trace elements). Diamonds are the hardest gemstones, ranking number 10 on the Mohs Hardness Scale. Even its name, diamond, is rooted in the Greek adamas, or unconquerable. The only object that can scratch a diamond is another diamond. Diamonds are formed deep within the earth at very high temperatures (1,652–2,372 degrees Fahrenheit at depths between 90 and 120 miles beneath the earth’s surface) and are carried up by volcanic activity. Diamonds are quite rare, according to the Gemological Institute of America, and only 30 percent of all the diamonds mined in the world are gem quality.

In the 1950s, the Gemological Institute of America developed the 4Cs grading system to classify diamonds: clarity, color, cut and carat weight. Not all diamonds are created equal (there are diamonds, and then there are diamonds). The value of the diamond depends on the clarity (flawless diamonds are very rare but a diamond's value decreases if there are many blemishes or inclusions), color (the less color the higher the grade), cut (how the diamond’s facets catch the light, certain cuts of diamonds show off the stone better than others) and carat weight (the bigger, the better).

When you start shopping for a diamond engagement ring, always prioritize the cut, which plays the largest role in the diamond's beauty (taking the time to clean your diamond ring at least every six months or so plays a role in maintaining said beauty). And on 1stDibs, a range of buying guides can be found for those in the market for antique engagement rings, vintage engagement rings or Art Deco engagement rings. 

Shop antique and vintage diamond rings, diamond necklaces and other extraordinary diamond jewelry on 1stDibs.