Diamond Buying Guide

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At J. Mullins Jewelry & Gifts, we understand the importance of choosing the best diamond for you. Our guide below will make your diamond buying an easy and more enjoyable experience.

The most important criteria that a jeweler uses while grading a diamond are cut, clarity, color and carat weight. It’s commonly know as the four C’s of a diamond. Together, these four properties will determine how much a diamond is worth.

The Four C’s Of Diamond Buying


Most often a person gets confused and thinks that the cut is the shape of the diamond, but the cut actually refers to the angles and proportions of a diamond. Diamond cut is considered to be the most important of the four C’s, so it is important to understand how the cut affects the properties and the value. Diamonds that are either cut too deep or too shallow can lose or leak light through the sides and bottom causing them to be less brilliant, ultimately causing the diamonds to lose their value. A well cut diamond is able to handle light better, creating more scintillation and sparkle, which leads to brilliance.


Diamonds are graded for clarity under 10X scope magnification. Clarity ranges from flawless (perfect) to I (included). Below is the chart that certification societies have standardized for grading to describe the clarity of a diamond.


A diamond’s color is usually referring to the presence or absence of color in white diamonds. Diamonds act as prisms and can divide light into a spectrum of colors and reflect this light as colorful flashes referred to as fire. The more colorless a diamond is, the more colorful the fire will appear. Diamond colors usually range from D to Z for white and yellow diamonds. D is the whitest. Around S they become “fancy” yellow diamonds.


This is the weight of the diamond measured in carats. One carat is equal to 200 milligrams. Sometimes one carat is referred to 100 “points”, so that a diamond of 75 points weighs .75 carat. Carat-weight is the easiest of the four C’s to determine. However, two diamonds of equal weight can have very unequal value, depending on their cut, color and clarity. Larger diamonds typically cost more per carat due to their size. Diamond cost increases exponentially with an increase in weight because larger diamonds are rarer than smaller diamonds and this rarity increases the value of larger diamonds.