What You Need to Know About Different Types of Diamonds

Are mined and lab-grown the same? Find out here.
sarah hanlon associate editor the knot
by Sarah Hanlon
sarah hanlon associate editor the knot
Sarah Hanlon
Associate Editor
  • Sarah is an Associate Digital Editor for The Knot, with special focuses in fashion, pop culture and wedding trends.
  • Before joining The Knot Worldwide, Sarah was a contributing writer for Bravo at NBC Universal.
  • Sarah has a degree in journalism and resides in New York City.
Updated Dec 10, 2021
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We'll let you in on a secret: Not all diamonds are created equally. While some may look the same to the naked eye, each diamond has the potential to be completely different. There are so many types of diamonds on the market today, from raw to lab-grown. So, when it's time to shop for an engagement ring, it can be helpful to know exactly what your options are.

In addition to understanding diamond shapes, ring metal types and the 4Cs (AKA the classification system used to grade diamonds), you'll want to familiarize yourself with the different types of diamonds available for purchase. Because, believe it or not, there are plenty of them! And, ultimately, the type of diamond you choose will impact what your engagement ring looks like, as well as how much it costs.

We tapped industry experts to share exactly what you need to know about the most common types of diamonds. Below, brush up your jewelry terminology before starting to shop for an engagement ring—that way, you'll know everything you need to before securing the perfect sparkler.

What is a Diamond?

According to The Knot 2021 Jewelry and Engagement Study, which surveyed over 5,000 couples who get engaged in 2021, 85% of all engagement rings include a clear diamond, proving its unwavering popularity. But before we define common types of diamonds, it's important to know what a diamond actually is. This beloved engagement ring center stone is a solid form of the element carbon. Its atoms are arranged in a crystal structure called diamond cubic. "Natural diamonds were formed about 100 miles below the earth's surface from one to three billion years ago, making them older than life on earth," says Grant Mobley, Diamond & Industry Expert from the Natural Diamond Council. "They form under rare conditions of extreme heat and pressure inside the earth that causes carbon atoms to crystallize. Millions of years ago, ancient volcanoes blasted toward the surface, trapping diamonds in their lava and bringing them close enough to the surface for us to find."

According to the Gemological Institute of America (GIA), a diamond is the hardest gem on the market. In fact, diamond is also the strongest substance on earth—it's 58 times harder than any other materials found in nature. Because of this, diamonds are expensive gems. A diamond's value is found in its colorless hue and purity, otherwise known as its lack of inclusions within the stone.

This is where the 4C's come into play. A diamond's cut, color, clarity and carat weight influence how much it costs. A colorless diamond ring with flawless clarity and a high carat size will be much more expensive because of its rarity. Jewelers use the 4C's as a guide to help customers choose the right diamond for their budget, as well as their preferred aesthetic.

Diamonds are also classified into five different types depending on their nitrogen atom impurities: Type I: (Type IA diamonds, Type IB diamonds, and Type IAB diamonds) and Type II (Type IIA diamonds, and Type IIB diamonds.) Their nitrogen impurities are measured at the atomic level within the crystal lattice of their makeup. Unlike inclusions, which can sometimes be seen by the naked eye, these impurities require an infrared meter to detect. Because this is high-level industry terminology, you don't have to worry too much about the type of a potential diamond. Your jeweler or gemologist will help you navigate these terms as you shop for a ring.

So, what types of diamonds are available to the consumer? We define them below.

Mined Diamonds

Mined diamond engagement ring
David Shao/Shutterstock

When you think of a "natural diamond," you most likely think of a mined diamond. For years, mined diamonds have been the most common choice for engagement rings and wedding bands. "Mined diamonds form deep in the earth's crust under immense heat and pressure over billions of years before they're recovered by mining operations," explains Madeline Fraser, founder and CEO of Gemist.

According to the GIA, the earliest diamonds were sourced from water banks in India. The diamond industry we know today, though, began in Africa, where diamonds were discovered in 1866. Over 20 years later, entrepreneur Cecil Rhodes launched De Beers Consolidated Mines in 1888. Then, by 1900, De Beers controlled about 90% of the world's production of rough diamonds. Today, the 50 largest mines account for about 90% of the world's supply of diamonds.

Because mined diamonds are the rarest diamond (as opposed to a lab-grown stone), they're valued higher. "Natural diamonds obtain their value from their scarcity as a natural, billion-year-old precious gem," Mobley says. "They've also shown to grow in value over decades as they become rarer.

Lab-Grown Diamonds

In recent years, lab-grown diamonds have emerged as an alternative way to source these gemstones. Thanks to advanced technology, it's possible to create diamonds in a laboratory, rather than mine them from the earth. And, ultimately, a lab-grown diamond is a true diamond. "A lab-grown diamond's makeup is identical to a mined diamond; the only difference is its origin," explains Don O'Connell, CEO and President of Charles & Colvard. "As opposed to being mined from the earth, lab-grown diamonds are made from carbon, and are therefore chemically, optically and physically identical to mined diamonds."

There are two ways that man-made diamonds are created. The first method, called High Temperature, High Pressure (HTHP), uses presses to mimic the environment found in the earth's crust. A diamond seed is exposed to intense heat and pressure, which forces it to grow into a fully-formed diamond. The second process uses Chemical Vapor Deposition (CVD) to grow a diamond from a hydrocarbon gas mixture.

Both of these methods can create a true lab-grown diamond in about two to three weeks—significantly less time than the three billion years it takes to create a mined diamond. After both methods, jewelers cut and polish lab-grown diamonds exactly like they would a mined diamond. And, because it's made of the same carbon makeup, a lab-grown diamond will shine just as bright as a mined diamond.

Despite this, there can be some difference in price between a lab-grown and a mined diamond. "Lab growns are less expensive than natural diamonds," explains Nicole Wegman, founder of Ring Concierge. But, she notes that a lower price can also equal lower value over time. "Since there is a continuous supply of lab-grown diamonds, there is less certainty in their long-term value as opposed to a natural diamond," she adds.

It's important to clarify the societal impact lab-grown diamonds have on the jewelry industry. While the diamond industry is committed to ethically-sourced gemstones, lab-created diamonds ensure a conflict-free production process. However, while some call lab-grown diamonds an eco-friendly alternative, the production process still leaves a carbon footprint, as with anything that involves a large output of energy.

Raw Diamonds

raw diamond
DmitrySt/Shutterstock

As you learn more about different types of diamonds, you may come across the phrase "raw diamond." Simply put, a raw diamond is one that has not been polished or cut. (Read: It's the diamond in its original form, not the sparkling stone you're used to seeing on engagement rings.) Because it's not a cut diamond, it tends to look cloudier than a traditional white diamond thanks to its rough, jagged edges. A raw diamond isn't technically a perfect diamond, but this style has certainly risen in popularity when it comes to engagement ring center stones. Its rustic, edgy finish is actually desirable to those who want a unique piece of jewelry.

Natural-Colored Diamonds

Natural yellow colored diamond engagement ring
STUDIO492/Shutterstock

While many diamond engagement rings are colorless, that's not always the case. In fact, diamonds come in all colors and patterns, from canary yellow to speckled salt and pepper—and they can definitely be used as center stones. "Natural diamonds form in many different colors, with the most common being brown," says Fraser. "In rare instances, natural diamonds can be pink, red, blue, purple or even green. These colors are extraordinarily scarce, though, and are caused either by slight changes to the molecular structure or by trace impurities."

Fancy-colored diamonds are still true diamonds and are not to be confused with colored gemstones like sapphires, emeralds or rubies. "A natural colored diamond is still a diamond made of the same element structure as natural colorless diamonds," Fraser adds. "Gemstones make up the rest of the jewels you see in jewelry, and they come in a vast array of mineral types, each with their own unique set of properties, colors, structures and compositions."

As you're shopping, it's important to note that naturally colored diamonds are not commonly found in stores. "True fancy colored diamonds are a very rare occurrence," Mobley says. "According to the GIA, only about 0.4% of diamonds graded in the last 20 years were a fancy color diamond." Be wary of stones marked as true fancy colored diamonds, as most options are color-treated instead of natural. "Not all retailers have experience with fancy colors, so seek out an experienced source with the knowledge and resources to help guide your purchase," Fraser adds. "Beware of undisclosed treatments, temporary coatings, or 'too good to be true' pricing that might indicate you're not getting a natural, untreated, fancy-colored diamond."

Color-Treated Diamonds

If you have your heart set on a blue diamond or a stone with a pale pink tint, you can still get one that's color-treated to your preference. "Colorless diamonds can be color-treated using several different methods," Mobley explains, adding that any sort of color addition is irreversible. "Color treatment is usually only done to a natural diamond with a color that already caused it to have a lower value than a colorless diamond. Color treatments can sometimes improve the look without lowering the value further."

And, when it comes to spotting the difference between a color-treated stone and a naturally-colored stone, that's something only a professional can do. "To the naked eye, it's hard to spot the difference between a naturally colored diamond and a color-treated diamond," Wegman explains. "Only a gemologist would be able to spot the difference."

Simulated Diamonds

While mined and lab-grown diamonds are chemically the same, these are very different from simulated diamonds. This variety does not have the same chemical makeup as the diamonds you'd find in the earth's crust or produced from HTHP or CVD.

Simulated diamonds can be used as an alternative engagement ring center stone. While they're not as valuable as diamonds, they are much more affordable and can appear to have similar qualities—though, it's worth noting that some simulated diamonds can look different from mined or lab-grown diamonds to the naked eye.

Simulated diamonds can come in a variety of materials like graphite or cubic zirconia. Perhaps one of the most well-known synthetic materials, though, is moissanite. "Moissanite is a naturally occurring mineral, silicon carbide, but there's only a very limited amount on earth as it is incredibly rare," says O'Connell, noting that Charles & Colvard was the first brand to bring moissanite to market. "The primary difference between diamonds and moissanite lies in their chemical composition. Moissanite is made of silicon carbide, and a diamond is made of carbon."

In fact, moissanite is rapidly growing in popularity, especially among young consumers. According to The Knot 2021 Jewelry & Engagement Study, 10% of couples opted for a non-diamond center stone—and of that group, 28% chose moissanite, which is up from 19% in 2019.

Because they're made through separate processes, moissanite and diamonds have a distinctly different look. Moissanite gems are double refractive, unlike diamonds—this means that moissanite stones are much more radiant and sparkly to the naked eye than a diamond. These gemstones tend to have different costs too. "While lab-grown diamonds and moissanite are comparable in price, moissanite often comes at an even more accessible price point," O'Connell adds.

When shopping for an engagement ring, be very selective about the kind of diamond you're purchasing. Simulated diamonds can be fair alternatives, especially if you're on a budget and you like their appearance. But, if you do want a diamond, make sure your gem is GIA certified before you purchase it to avoid misleading sales.

With so many types of diamonds available, it might feel downright impossible to pick just one. Ultimately, there's no wrong choice—it all comes down to your personal style. "From colorless to fancy-colored or even semi-polished raw diamonds, there are no limitations on the beauty that comes from the earth," Fraser says. "Your engagement ring should help tell the story of your love, and choosing a diamond that reflects your unique story is a wonderful way to celebrate."

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