Diamond Buying Guide Skip to content


Your cart is empty

Diamond Buying Guide

Investing in a diamond is a big decision. Read on to learn about the five characteristics of a diamond, diamond shapes and diamond grading reports. Still have questions? Our expert team is happy to help with all your diamond-buying needs.

The 5 C’s of Diamonds

You may have heard of the 4 C’s of Diamonds. These refer to the four main characteristics that are important to understand when shopping for a diamond. At E.M. Smith, we include a fifth “C” for confidence. That’s the secret ingredient for finding a stone that suits you. Don’t worry if you’re not quite sure yet. We’ll give you the tips you need to select the perfect stone for you.


"Carat" is a unit used to measure a diamond’s weight. In ancient times, the original "carats" were seeds from the carob tree, native to certain Mediterranean countries.  Because the seeds were extremely uniform in size and weight, they were used for weighing pearls and precious stones. Today, the modern carat weighs 1/142 of an ounce, or in metric terms, 200 milligrams.


Virtually all diamonds carry birthmarks given to them when they were formed many billions of years ago. In the diamond business we call these marks inclusions. A clarity grade is assigned to each diamond based on the size, number and location of its inclusions. The fewer the inclusions and more difficult they are to see under a gemologist’s microscope, the higher the clarity grade of the diamond and the higher the price it commands. A diamond with large visible inclusions will typically be assigned a lower grade and lower price.


Color refers to the body color of the diamond when it is laid top-down and viewed against a white background using natural north daylight. An actual color grade is assigned to a diamond by comparing it side by side with other diamonds of known color grades. The more colorless the diamond, the higher the color grade and the higher the price it commands. Diamonds with more yellow or brown hue typically fetch a lower price.

A few very rare diamonds have brighter tints of color (usually yellow, brown, green, blue or pink) that make them heavily sought after by both consumers and collectors.


As far as beauty is concerned, cut is the most important of all diamond characteristics. It refers to how the dimensions of a diamond are proportioned and how the surfaces are positioned to create sparkle and brilliance. Only through skilled cutting and polishing is the brilliance and sparkle of a diamond released. Even a diamond that is of fine color and clarity may fail the "looks" test and be worth substantially less if it has been poorly cut.


The variables that affect a diamond’s value are so nuanced, most people need help understanding what they’re paying for. Here are a few tips that can help you make an informed, confident decision.

1.  Talk to friends and family who have purchased diamonds. Find out if they were happy with their experience.

2.  Shop around. Go to several stores and ask lots of questions.

3.  Check out the credentials of any store you are considering buying from. Make sure the store you are considering has a GIA (Gemological Institute of America) trained gemologist on staff.

4.  Be sure to ask about refund policies and guarantees.

5.  The internet is a great place to gather information. But spending thousands of dollars online is risky when there’s no way to know what the diamond actually looks like. Two diamonds that weigh the same and have the same color and clarity grade can look entirely different. We recommend shopping in-store and seeing diamonds in person.

Diamond Shapes

Choose a diamond shape that suits your style. Explore popular round brilliant diamonds, or shop for alternative shapes. Read on for more information or visit us in-store to browse diamond shapes in person.

Round Brilliant Diamonds

Approximately 80% of all diamond engagement rings purchased today will be set with a round brilliant diamond. The round shape lends itself to maximum light reflection and is considered the most brilliant and classic of all the diamond shapes. Because of its popularity, the round brilliant carries a slightly higher price than many of the less requested shapes.

Explore Alternative Shapes

For a more unique look, you might prefer an oval, marquise, emerald cut or pear shaped diamond.  In the past few years, the princess cut has been extremely popular. Because the market is full of new and interesting shapes, we recommend that you keep an open mind and shop a variety before you choose.

Laboratory Diamond Grading Reports

When shopping for a diamond, you’ll find that many sellers provide laboratory diamond grading reports. These reports provide some quantifiable information about a diamond, but does it really tell the whole story? We’ll answer some of your questions below.

What is a grading report?

When you shop for a diamond, you’ll notice that many diamonds are accompanied by a grading report from one of dozens of different gem laboratories. A grading report quantifies diamond characteristics like cut, clarity and color, assigns a “grade,” and is meant to provide a clear, accurate assessment of the diamond.

Can I trust a grading report?

Though some laboratories are reputable, others are not. Some may intentionally “fudge” their report to help the jeweler, resulting in a document that misinforms the buyer. Even in a less nefarious scenario, grading sometimes lacks consistently between one lab and the next. Those who shop online are particularly vulnerable because the buyer is only aware of what the report says without the ability to see the diamond in person.


At the end of the day, a grading report can’t tell you what a diamond actually looks like. We like to compare it to choosing your spouse based on their driver’s license description. Their driver’s license may tell you details about them: 5’7” weighs 130 lbs, blonde hair and blue eyes. But could you pick that exact person out of a crowd of people with similar characteristics? Similarly, a diamond’s color, clarity, grade and measurements simply don’t tell you what it looks like. In fact, two diamonds with identical measurements and grades can look completely different and hold vastly different values.

Select the Perfect Diamond When You Shop In Store

In order to choose the most beautiful diamond for your money, you simply must see it. We strongly recommend buying your diamond from a reputable jeweler who can show you a number of diamonds, let you compare them side by side and also provide a lab report if desired. If a lab report is important to you, AGS and GIA are the most reputable labs. 

Our expert team members at E.M. Smith are happy to provide you with all the information you need to make the right selection. Compare diamonds in person, so you can pick the one that’s right for you.

Start Your Project