Be Brilliant. Get Smart. Buy Beautiful.

Everything you need to know about diamond buying:
responsible sourcing, diamond quality, the 4C's and beyond.

Beyond the 4C's

Discover how we hand-select the most visually beautiful diamonds - there's more to it than meets the eye.

At Robbins Brothers, our Buyers see literally thousands and thousands of diamonds before making a selection.Their critical eye results in over 90% being rejected.

This ensures that every diamond we sell is a truly beautiful diamond. They go beyond the 4C's to make your diamond the ideal diamond for a truly beautiful engagement ring.

The 4C's

While the 4C's are not the be-all, end-all when it comes to diamonds, you should have a basic understanding of what they measure and describe before you buy.


A well-cut diamond will direct more light through the crown. A diamond with a depth that's too shallow or too deep will allow light to escape through the sides or the bottom of the stone.

Diamond Cut Quality - 4C Education


The color of a diamond ranges from an icy white colorless to a light yellow. It's very difficult to tell the difference from one color grade to another color grade. That's why it's important to compare diamonds side by side. Colorless is the most rare and therefore the most expensive. Yellow is the least rare and therefore the least expensive.

Diamond Color - 4C Education


The Clarity Effects the Rarity and Therefore the Expense.

The clarity refers to the diamond's tiny markings. GIA created a grading scale to help the consumer understand what makes one diamond worth more than another. The grading scale is based on rarity. Flawless is the most rare and therefore the most expensive. Included 3 is the least rare and therefore the least expensive.

Diamond Clarity - 4C Education

Carat Weight

Many People Want the Largest Diamond They Can Afford.

1 carat is divided into 100 points so that 50 points is 1/2 carat. Although size is an important factor in determining the value of a diamond, the cut, color, and clarity are equally important.

Diamond Carat Weight - 4C Education


Your guide to the standard 4C's.

The diamond certificate tells you all of the measurable facts about your diamond. It has information on the 4Cs and shows you any flaws your diamond may have.

This is your starting point when judging a diamond. But it is only a starting point. The "cert" cannot show you how beautiful your diamond is, it can only measure quantifiable aspects. And beauty is not quantifiable.

Diamond Certification - 4C Education

Diamond Quality

Your Diamond should last a lifetime. We cut facets, not corners.

Our diamond buyers reject 9 out of every 10 diamonds shown to them. These rejected diamonds are then sold elsewhere - never at Robbins Brothers. The beauty is in the details.

What Makes Quality Diamond


Since the inception of Robbins Brothers, we have been unilaterally against the importation of conflict diamonds. We do not sell Conflict Diamonds. Ever.

We never sell Conflict Diamonds

Robbins Brothers has proudly vowed to always follow a rigid policy that ensures the diamonds we purchase are mined and distributed under the highest ethical standards.

What are "Conflict Diamonds"?

Conflict Diamonds are diamonds that originate and are mined from areas controlled by forces at war, or otherwise in armed conflict with the region’s existing officially recognized government. The diamonds produced from these areas are used to illegally and often brutally fund military action in opposition to those governments, or in contravention of the decisions of the United Nations Security Council. Conflict Diamonds are also sometimes referred to as “Blood Diamonds.”

The Kimberley Process

In May 2000, Global participants came together in Kimberley, South Africa to create and implement standardization of certification among diamond exporting countries, thereby creating common language, transparency, auditing and monitoring of diamond exportation. Since the Kimberley Process has been put in place, the DTC reports that 99.8% of imported diamonds are certified conflict-free.

What Are Conflict Free Diamonds

Clean Diamond Trade Act

In May 2000, the U.S. Government signed the Clean Diamond Trade Act, which enables the U.S. to implement the procedures developed by more than 50 countries to exclude rough conflict diamonds from international trade, while promoting legitimate trade. The Clean Diamond Trade Act is aimed at protecting the legitimate diamond industry.

Certificate of Origin

A well structured Certificate of Origin regime has proven to be an effective means of ensuring that only “legitimate diamond”, that is, those only from conflict-free government controlled areas, reach the world market. New legislation now levies significant sanctions against those who fail to comply, barring their access to the legitimate diamond market.

Diamond Shapes

Now it's time for a little fun. Looking for a diamond that's a classic or a totally unique shape? You decide. We've got the widest array of cuts, shapes and settings to choose from. One of which will match your style to perfection.


From the hands of an expert cutter, the Round Brilliant diamond delivers on its promise of "beauty and brilliance." This is the classic shape for diamonds and a well cut Round Brilliant maximizes light return better than most other shapes and creates a dazzling display, sure to make her heart skip a beat and her friends jealous.


The Princess Cut combines the liveliness of a Round diamond and the contemporary shape of an Emerald or Square cut to create one of the most brilliant fancy shapes of all.


An Emerald Cut diamond is an elegant beauty. It has a rectangular shape with cut corners which is also known as a step cut (because its concentric, broad, flat planes resemble stair steps). Looking into an Emerald Cut diamond is like looking into a clear pool of water - it draws you in.


The Cushion Cut is an elegantly shaped diamond that has recently gained popularity because of the heightened demand for vintage-styled jewelry. Combining the cut characteristics of both the round and the oval, the Cushion Cut's rounded corners and larger facets increase this special diamond's brilliance.


While the silhouette of a Radiant reminds us of the elegant Emerald cut, the Radiant's facet pattern is arranged to create a much more brilliant return of light - befitting its name - Radiant.


The Asscher diamond is named after Joseph Asscher who developed the cut in 1902. The Asscher has a similar facet arrangement to the Emerald Cut yet is square rather than elongated in proportion. The Asscher has 74 facets which make this special cut reminiscent of a bygone era. The Asscher has regained popularity as a result of the many famous stars opting to wear this vintage cut diamond.


The Pear Cut diamond combines the cut characteristics of the Round Brilliant and the regal Marquise to form an elegant, beautiful and brilliant cut of diamond. Also known as a "teardrop," this cut of diamond is sure to bring a tear of joy when it is given to the one you love.


The Oval Cut diamond gives a softer, rounder look that, along with its elongated shape and amazing sparkle, truly captures the viewer's attention.


True romantics love the Heart Shape! The two soft shoulders that lead down to one lower point...the point where two become one.


With its design, said to be inspired by the fetching smile of the Marquise de Pompadour, the Marquise cut diamond's elongated shape flatters the hand and symbolizes true love to last the ages.