Planning to buy a diamond engagement ring? You’ll need to know the 4Cs, how to pick a diamond shape and cut, metal characteristics, types of settings and more.

Follow these 12 tips for buying an engagement ring to make a smart purchase:

1. Know the 4Cs
2. Understand the difference between diamond shapes, diamond cutting styles and diamond cut quality
3. Pick a metal for the band
4. Choose the setting
5. Pick side stones
6. Look at a diamond under different lighting conditions
7. Get the most sparkle and size
8. Pick a ring that suits her style (not yours)
9. Know her ring size
10. Decide how much to spend
11. Pick a jeweler
12. Insist on a diamond grading report

1. Know the 4Cs

The first tip for buying a diamond engagement ring is to know the 4Cs: Color, Cut, Clarity and Carat Weight. Created by GIA, the 4Cs are the global standard for assessing the quality of diamonds and allow you to compare one diamond to another.

In brief, the 4Cs are:

  • Color: D-to-Z diamond color grades rate a diamond’s lack of color. Diamonds with less color are rarer.
  • Cut: The quality of a diamond’s cut determines how well it unleashes its light.
  • Clarity: Diamond clarity refers to the absence of inclusions and blemishes.
  • Carat Weight: Diamond carat weight determines a diamond’s apparent size.
Once you understand what the 4Cs mean, the next step is to ask yourself “What is the most important C to me?” Prioritizing the 4Cs will help you quickly eliminate some diamonds from your search, and zero in on ones that will thrill your bride-to-be.

Understanding the 4Cs is worth your time: It is the universal language to describe diamond quality. Being able to speak this language empowers you to buy a diamond engagement ring with confidence.

2. Understand the difference between diamond shapes, diamond cutting styles and diamond cut quality

Before you start shopping for an engagement ring, you should understand the difference between a diamond’s shape, its cutting style and its cut quality. Shape describes a diamond’s outline when viewed face up.  By far, the most popular diamond shape is round. But there are other shapes —known as fancy shapes— which include the marquise, pear, oval, rectangle, square and heart.

Cutting style refers to how the diamond’s facets are arranged.  For example, the most common facet arrangement for round diamonds is the standard brilliant cutting style with a specific arrangement of 57 or 58 facets.  Other cutting styles include the emerald cut, which is a square or rectangular shape that is categorized by four longer facets along the sides (step cuts) and beveled corners.  A radiant cut diamond also has a square or rectangular shape, but is cut in the brilliant style.

Cut quality refers to how well a diamond’s facets interact with light. Diamonds cut in the same shape and style can vary in table size, girdle thickness, polish and symmetry. These differences have an effect on their face up appearances and will impact their cut quality.

A range of fancy diamond shapes and cuts.

Here are some fancy diamond shapes and cuts. From left to right, they are: a 1.04 carat (ct) cushion cut, a 1.30 ct Asscher cut, a 1.05 ct emerald cut, a 1.03 ct modified radiant cut, a 1.01 ct oval, a 1.01 ct marquise and a 1.04 ct pear. Photo: Robert Weldon/GIA

3. Pick a metal for the band

The type of metal you pick for an engagement ring band affects the overall look of the piece. White gold and platinum have been popular for a number of years, and both make for a sleek, modern look. They are also good choices for diamonds graded in the colorless to near-colorless ranges–D through J on the GIA color scale—as they highlight the diamond’s colorlessness. Setting one of these diamonds in yellow prongs would cause the diamond to look more yellowish in appearance.

If you love the color of gold, consider that white metal prongs or bezels are often integrated into yellow gold bands to create contrast with the diamond. Rose gold is trending, has a warm and soothing appearance, and was a popular choice for engagement rings from the Retro era (1935 to the 1950s).

Here is some important information on these metals:

  • Platinum is a gray-white metal that is elegant, extremely durable and corrosion resistant. Because platinum is soft in its pure state, it is typically alloyed with other metals such as iridium, ruthenium and cobalt, the most popular alloys in the U.S. According to the U.S. Federal Trade Commission, only jewelry containing 950 platinum (95% platinum and 5% alloys) can be marked “Platinum”; settings with 90% or 85% platinum (”traditional platinum”) must be marked accordingly: e.g., 850Plat or 850Pt. Settings that contain 50% to 80% platinum must also include the percentage of each alloy (e.g., 800 Pt. 200 Ir., for platinum alloyed with iridium). Platinum is generally more expensive than gold, but it is also hypoallergenic and more durable.
Platinum radiant cut diamond engagement ring in a bypass setting.

Platinum’s beauty and durability make it a popular choice for engagement rings. Courtesy: Ritani

    • Gold has been used in jewelry for thousands of years. It enchants because of its color, rarity and luster (the appearance of a material’s surface in reflected light). Like platinum, pure gold is soft, so it is typically alloyed with other metals. Karat is the term used to state gold’s fineness, which is based on 24 parts. Gold that is 75% pure—18K gold—is 18 parts gold and six parts an alloying metal. The most popular karatage in the U.S.—14K gold—is 14 parts gold and 10 parts another metal.

Rose gold is usually made by alloying gold with copper and silver. Companies closely guard their special blends. Rose gold is usually more durable than yellow gold, and is said to complement any skin tone.

A 2.04 ct oval diamond is set in 18K rose gold

Representing a popular trend in engagement rings, this 2.04 ct oval diamond is set in 18K rose gold. Courtesy: 1stdibs.com

– White gold is made by alloying pure gold with white metals such as palladium or silver. It is a beautiful and durable choice for engagement rings. Note, however, that white gold is usually plated with rhodium for a better shine and to protect against scratching. This can wear away over time, requiring replating.

  • Sterling silver is often used in jewelry but rarely in engagement rings, as it is not the most durable of metals and tarnishes over time. It is also comparatively soft. Sterling silver is an alloy of 925 parts (92.5%) silver and 75 parts (7.5%) copper or other metal (usually nickel or zinc).

4. Choose the setting

In an engagement ring, a diamond is held in place by a setting. The setting has two jobs: to highlight the beauty of the diamond, and to protect it from damage. Different settings offer different degrees of protection.

Here are three common types of settings:

  1. Prong: A diamond is held in place with four to six prongs (narrow metal supports). When prongs are used to secure a single stone, the ring is often called a “solitaire.” There are many variations to the prong setting, like the cathedral setting, which has slopes extending into the band from each prong, to further protect the diamond.
Diamond solitaire engagement ring in a six-prong platinum setting.

The six-prong setting in this solitaire engagement ring provides extra security for the diamond. Courtesy: JK & Co Jewelers

  1. Bezel: For this engagement ring setting style, a thin metal strip is pushed or hammered around the gem to hold it in place. The bezel setting provides excellent protection for the center stone.
A 2.03 ct fancy vivid yellow diamond engagement ring set in platinum with an 18K gold bezel.

The 2.03 ct fancy vivid yellow diamond in this platinum engagement ring is well protected by an 18K gold bezel. Courtesy: EraGem.com

  1. Halo: Tiny diamonds encircle the center stone. A halo can add more sparkle to an engagement ring and make the center stone look larger.
A 1 ct round brilliant diamond engagement ring surrounded by a double halo of melee diamonds set in white and rose gold.

A double halo of melee diamonds set in white and rose gold makes the center round brilliant in this engagement ring appear larger. Courtesy: Sylvie Collection

5. Pick side stones

Side stones are a dazzling way to dress up an engagement ring. They bring a dash of elegance, creating a look that’s simply sophisticated. Popular choices include channel or pavé set diamonds along the shank of the ring, diamond baguettes on either side of the center stone, and colored gems in any number of configurations. If you want diamond side stones that complement the center stone, choose ones that grade close to the center diamond in color, clarity and (if round brilliants) cut.

A 1.4 ct pear shaped diamond engagement ring accented by two tapered baguettes.

This 1.4 ct pear shaped diamond is accented by two tapered baguettes. Courtesy: EraGem.com

A diamond and sapphire three stone engagement ring.

The two sapphires in this engagement ring make the diamond center stone pop. Courtesy: Omi Privé

6. Look at a diamond under different lighting conditions

Daylight, candlelight, fluorescent lighting, spot lighting – a diamond looks very different under various lighting conditions. The reason: A diamond’s facets act like tiny mirrors, reflecting their surroundings. Any movement causes the facets to reflect light onto each other, producing mesmerizing flashes of light and color. When buying a diamond engagement ring, be sure to look at it under these four different lighting conditions to see how it performs:

  1. An environment where spot lighting is not overwhelming
  2. Diffused lighting—fluorescent lights that bounce light off a white ceiling are best
  3. A mixed lighting environment of spot and diffused lighting
  4. Natural daylight – directly under the sun, or under the dappled shade of a tree that breaks up the diamond’s light into thousands of slivers
Also consider where your bride-to-be will wear her engagement ring most. You’ll want to choose a diamond engagement ring that performs best in this environment.

7. Get the most sparkle and size

For diamonds of similar color and clarity, the cut is responsible for the stone’s sparkle. A simple tip to make sure a round brilliant diamond sparkles is to pick one that has a GIA cut grade of “Excellent” or “Very Good.” In addition, as a general rule, the more diamonds an engagement ring has, the more the engagement ring will sparkle. This is another reason to consider diamond side stones.

A diamond displaying an “Excellent” cut grade.

This diamond has an “Excellent” cut grade. It is very bright and shows an even pattern with good contrast between light and dark areas. Reflections appear crisp and well balanced. If all else is equal, an Excellent cut grade pretty much guarantees an extremely attractive diamond. Photo: GIA

A diamond displaying a “Good” cut grade.

This diamond has a “Good” cut grade. Its bright reflections aren’t as sharp and there’s more darkening around the girdle. Photo: GIA

This diamond displays a “Poor” cut grade.

This diamond has a “Poor” cut grade. The dark areas are significantly more prominent and the bright areas are much smaller. Photo: GIA

Here are two ways to make your diamond engagement ring look bigger:

  1. Set the diamond in a head made of fluted white metal, an illusion setting. The diamond will appear to be the size of the entire head.
A round brilliant diamond engagement ring in an illusion setting.

The total weight of the diamonds in this engagement ring is 0.12 carats, but the illusion setting makes them look far larger. Courtesy: EraGem.com

  1. Use a cluster setting: Place several small diamonds of similar size next to one another. This technique maximizes sparkle and gives the illusion of a single diamond that is much larger in size than the melee diamonds used to make it.
A cluster engagement ring setting creates the illusion of three large gems.

This cluster engagement ring setting creates the illusion of three large gems using only 0.29 carats of melee diamonds. Courtesy: EraGem.com

8. Pick a ring that suits her style (not yours)

An engagement ring is intended to be worn everyday for life. It should make the wearer’s heart sing. That said, it’s time to put your own tastes aside and find out what style she prefers. The easiest way is to ask her, but if you want to protect the element of surprise there are other ways of finding out:

  • Observe. What style jewelry does she wear most often? What color metal?
  • Ask her best friend. Your intended may have created a Pinterest board of her dream engagement rings or jewelry. If she hasn’t shared it with you, chances are she has with her friend.
  • Go shopping for jewelry together. Pay attention to what draws her to a particular piece of jewelry.
  • Her style might be classic if she has a refined look and loves to surround herself with things that have an old-world elegance. An engagement ring featuring a single rectangular-shaped diamond or a round diamond faceted in the brilliant style are timeless choices that would probably suit her style.
A 5.09 ct cut-cornered rectangular step cut engagement ring flanked by two tapered baguettes.

A cut-cornered rectangular step cut is the embodiment of elegance. This 5.09 ct stunner is flanked by two tapered baguettes. Courtesy: 1stdibs.com

A 1.37 ct round brilliant diamond engagement ring in a six-prong setting.

A 1.37 ct round brilliant in a six-prong setting is likely to please a partner who prefers a classic look. Courtesy: 1stdibs.com

  • If she’s a romantic, a heart shaped diamond could quicken her pulse. With their bows and ribbons, Edwardian style engagement rings could also be a rich source of inspiration.
A 1.03 ct heart shaped diamond engagement ring set in platinum.

The romantic at heart is sure to fall for a heart shaped engagement ring. Courtesy: Leo Ingwer

Edwardian era engagement ring accented with diamonds and rubies.

Bows and ribbons adorned Edwardian era engagement rings, so this style will delight a romantic soul. Courtesy: Erstwhile Jewelry

  • If her tastes are modern, she probably embraces current trends and is not afraid to make a statement.
Matching diamond engagement ring and band set in rose gold and platinum.

Set in rose gold and platinum, this matching diamond engagement ring and band would please a modern bride. Courtesy: Sylvie Collection

Art Nouveau style engagement ring with two diamonds trailed by curving diamond-studded lines.

The two diamonds in this Art Nouveau style engagement ring are trailed by curving diamond-studded lines. Courtesy: 1stdibs.com

Fancy cut diamond Art Deco era engagement ring surrounded by rubies.

Geometric shapes were the building blocks of Art Deco jewelry, and this combination of a fancy cut diamond surrounded by rubies would make for a great engagement ring choice for your artsy bride-to-be. Courtesy: 1stdibs.com

9. Know her ring size

If you’re buying an engagement ring, but don’t know your beloved’s ring size, here are a few tips on how to (subtly) get it. Wait till she’s out of the room and then borrow a ring she owns and trace the inner circle on a piece of paper, or press the ring into a bar of soap and make an impression. You can also slide it down one of your fingers and draw a line where it stops. A jeweler can use these measurements to estimate her ring size. There are other ways to determine her ring size if she doesn’t wear rings.

10. Decide how much to spend

The bottom line: Spend as much as you think is appropriate.

We’ve debunked common diamond engagement ring myths before, and here’s a good place to debunk them again. The myth of spending three months’ salary on an engagement ring dates back to the 1950s and doesn’t have much merit. Here’s a far better tip: Learn the 4Cs, do some comparison shopping and find an engagement ring that fits your budget. In the end, it’s not how much you spend, but how much love the ring represents.

11. Pick a jeweler

Since an engagement ring is an expensive purchase, you’ll want to buy it from a jeweler you can trust. Tip – start by looking for a jeweler who has earned a credential from an accredited school like GIA. The GIA Retailer Look Up can help you find retailers who carry GIA-graded diamonds or have GIA-trained staff.

A gold diamond engagement ring.

An engagement ring is one of the most important purchases you’ll ever make, so pick a jeweler you can trust. Courtesy: Stuller, Inc.

12. Insist on a diamond grading report

When buying an engagement ring, insist on a diamond grading report. By giving you the exact quality characteristics of the diamond, the report will remove any uncertainty from your buying decision. The report will also indicate whether the diamond has been treated to enhance its color or clarity. GIA offers a variety of diamond grading reports.

A GIA Diamond Grading Report

A GIA Diamond Grading Report gives you peace of mind when you buy an engagement ring.

BONUS TIP: Insure your engagement ring

Once you’ve found an engagement ring that will make your sweetheart swoon, you’ll want to insure it. Should the ring ever be lost or stolen, you would receive fair compensation. Insurers typically require a diamond grading report before they will issue a policy, and that’s another reason to make sure your purchase comes with one.