Diamond Guide

Unicorn Jewelry Diamond Guide




At Unicorn Jewelry & Watch Boutique, we want you to find the perfect stone for your needs. That’s why we offer the largest collection of loose diamonds and designer diamond jewelry in San Diego. Our experts will work closely with you to walk you through the process of selecting the diamond of your dreams and help educate you on what qualities make for the most exquisite stone.

To help you through the diamond selection process and learn more about what makes each stone unique, please find our simple diamond guide below.

Diamonds are graded and categorized by the diamond industry using various characteristics of each stone. The first step to learning about diamonds is to familiarize oneself with the "four Cs", which are considered the most important grades and categories in a diamond’s quality:

Cut, Clarity, Color, Carat

And then there's the important, but lesser-known “fifth C": Certificates.

The diamond certificate, also known as the grading report, is a complete evaluation of a diamond that has been performed by a qualified professional with the help of special gemological instruments. Each stone bears its own individual and recognizable characteristics, which are outlined on the certificate.


Diamond Cut

The cut is considered the most important aspect of a diamond. It refers to the way the facets (sides) of a stone are aligned. The cut and its proportions are what enable a diamond to make the best use of light. Good proportions allow light to be refracted in a better way from one facet to another, giving a diamond the brilliant sparkle that we look for.

Common Diamond Shapes:

Round Diamond Shape
Round Brilliant
The round brilliant is the most popular of all the polished diamond shapes.
Oval Diamond Shape
The oval is an adaptation of the round brilliant and appears larger and longer than a round stone of the same carat weight.
Marquise Diamond Shape
The marquise is the name given to the diamond shape that is long and pointed at both ends.
Heart Diamond Shape
The heart shape is perhaps the most romantic of what are known as the fancy shapes.
Emerald Diamond Shape
The emerald cut is rectangular, with oblong facets on each side and across the corners.
Pear Diamond Shape
The pear shape is the English name for the French 'pendologue' (pendant), and is rounded on one end and comes to a point on the other.
Princess Diamond Shape
The princess cut is a square cut that creates a bright and scintillating look.
There are also several fancy shapes available, including triangular cut, star cut, trillion cut and many others.

How Cut Affects Light Reflection

ideal cut proportions

When a diamond is cut to ideal proportions, light is reflected from one facet to another and then dispersed through the crown (top) of the stone.

diamond cut is too deep

If the cut of the diamond is too deep, some light escapes through the opposite side of the pavilion (bottom).

diamond cut is too shallow

If the cut is too shallow, light escapes through the pavilion before it can be reflected.

The Ideal Cut

The first to discover the precise angles to which a diamond must be cut was Marcel Tolkowsky, a polish diamond cutter who made the finding in the early 1900s. Unfortunately, a truly ideal cut is possible only in a round cut diamond, where light is able to reflect off the 57 to 58 precisely-placed facets and then disperse throughout the top of the stone.

The quality of a diamond's cut depends on two major proportions:

  1. The depth percentage, which is a measurement of height vs. width; and
  2. The table percentage, which is the measurement of the diameter of the top facet vs. the average width of the diamond
Every loose diamond from Unicorn jewelry comes with a report that describes the depth and table percentage plus other measurements that are important to the stone's quality.

Diamond Clarity

Almost all diamonds contain minute traces of non-crystallized carbon or small non-diamond crystals. Most are not discernible to the naked eye and require magnification of at least 10x to become visible. These imperceptible flaws, known as inclusions, are nature's fingerprint and make every diamond naturally unique. However, the fewer there are, the rarer the diamond is considered. We recommend diamonds that have a clarity classified as SI2 or higher, meaning they are completely clean to the naked eye.

Classifications of Clarity

Internaly Flawless

These diamonds are internally and externally flawless. They are also the most rare and beautiful stones, valued for their purity.

Very, Very Small Inclusions

These diamonds have very slight inclusions that can be seen only through a microscope. The brilliance of these diamonds are not affected by the slight blemishes.

VS1 - VS2
VS1 - VS2
Very Slight Inclusions

The inclusions present in these diamonds can only be seen by a trained eye through a 10x lens. It is almost impossible to find the flaws with the naked eye.

S1 - S2
S1 - S2
Slight Inclusions

These diamonds have inclusions that are easily seen with a 10x lens and are sometimes visible to the naked eye. If you have a fixed budget, these stones will provide you with your best choice without sacrificing the beauty of the stone. We recommend that you do not purchase diamonds of a lesser grade than S1 - S2.

I1 - I3
I1 - I3

The blemishes in these diamonds can be located with a naked eye and will have an effect on the sparkle of the stones.

Diamond Color

Although the majority of diamonds appear to be colorless, others can contain tinges of yellow or brown, which are sometimes referred to as champagne diamonds. There are also rare diamonds, known as fancies, that come in exceptional colors such as green, red, blue, pink or amber.

The colorless grade of diamonds is considered to be most valuable. At Unicorn Jewelry & Watch Boutique, we recommend diamonds that will appear white when mounted in jewelry, which fall into the H - I color or better in the diamond color scale provided below.

Diamond Color Scale

As you can see, there are many subtle shade differences in diamonds. However, the closer a diamond is to colorless (D), the more valuable it is. Diamonds with no hint of color are very rare, as are fancies (color diamonds) with very strong shades of color. Nuances between color grades are very hard to distinguish and differences are usually judged through the pavilion side of a stone using a set of "master stones" for comparison.

Diamond Carat

Diamonds are sold by weight rather than size. The unit of weight is known as the stone's carat (ct), with five carats equal to one metric gram. Because the carat is a unit of weight rather than size, two different gemstone varieties - say a diamond and a ruby - can be different sizes although they are the same carat weight. In this case, rubies are denser than diamonds; therefore a one-carat ruby will be smaller in size than a one-carat diamond.

Diamond Carat

While carat weight is important, the millimeter size of a gemstone tells you exactly what size diamond will fit in a particular mounting. Just as there are 100 pennies in a dollar, there are 100 points (pts.) in a carat, with one point equaling .01 carats. For example, a diamond weighing .05 ct can also be referred to as a "five point diamond."

Due to the rarity of larger diamonds, their value is greater than a combination of several smaller diamonds. For example, a 2.0 ct diamond is worth more than two 1.0 ct diamonds.

It is also important to note that the carat weight of a stone (ct.) is different from the term karat (K), which is used in the United States to express gold quality (e.g., 14K gold).



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