How To Buy a Diamond

how to buy a diamond

With this guide you will understand the four C’s of determining a diamond’s value:

These guidelines will walk you through the steps of how to buy a diamond based on the same criteria jewelers and diamond dealers use to grade and evaluate them.

Before explaining the four C’s, we will introduce you to the grading report, which is more commonly known as the Diamond Certificate. This certificate documents the attributes of a diamond, including the four Cs, as noted by a gemologist.

Carat Weight

The weight of a diamond is measured in carats. The value tends to rise exponentially with carat weight, since larger diamonds are more rare. how to buy a diamond by carat weight - her dream diamond

Diamond Cut

The cut of the diamond can mean two things:

  • The shape of the diamond
  • Quality of the cut

The cut of a diamond has the most effect on its brilliance. A diamond which is well cut will have excellent light return and look larger and brighter. A poorly cut diamond can make a diamond look dull and dark.

Diamond Colour

The colour of a diamond is graded from pure white to a tinted brownish yellow colour. A letter graded is assigned for each colour grade. The purest white is a D colour followed be an E, F, G, H…….X,Y,Z. The most popular colour grades are D,E,F,G,H,I and J. The K colour and below can often appear yellowish to the untrained eye. The whiter the diamond the more rare and valuable it becomes.

how to buy a diamond by diamond colour - her dream diamond

Diamond Clarity

The clarity of a diamond is determined by examining a diamond face up under 10x power magnification. Nearly all diamonds have clarity characteristics that became part of the diamond when it was formed. The higher the clarity, the more valuable a diamond becomes.  In this tutorial you will see diamonds magnified to give an idea just how small some of these inclusions can be.

*Tip for researching clarity.

how to buy a diamond by diamond clarity


Many diamonds listed have certificates accompanying them. The five internationally recognized gem laboratories in the world are as follows:

  • GIA (Gemological Institute of America)
  • AGS (American Gem Society)
  • HRD (High Diamond Council)
  • EGL (European Gemological Laboratory)
  • IGI (International Gemological Institute)

In making a diamond purchase it is highly recommended that you read and review a copy of its certificate. The certificate is your indication of the quality and value of that diamond.

Are you ready to learn more about how to buy a diamond?

Go through our tutorial – Step 1