The Mastery

The Beauty of Ideal Cut

Light RefractionExternal brilliance is the light reflected from the surface of the stone—its luster. The quality of a finished stone’s polish will determine how well a diamond’s luster is borne out.

Internal brilliance is the percentage of incident light reflected back to the viewer from the pavilion facets. The goal is to attain total internal reflection by choosing carefully the crown and pavilion angle. If the pavilion is too shallow, light meets the pavilion facets within the critical angle and is refracted (or lost) through the bottom of the pavilion. If the pavilion is too deep, light is initially reflected outside the critical angle on the side of the pavilion, but meets the opposite side within the critical angle and is then refracted through the side of the stone.

The term scintillation brilliance is applied to the number and arrangement of light reflections from the internal facets; that the degree of “sparkle” seen when the stone moves. Scintillation is dependent on the size, number, and symmetry of facets, as well as the quality of the polishing.

The Grunberger Precision Cut® brings that knowledge to diamond cutting. We have managed to achieve such ideal precision in stones that we are capable of cutting as small as 1/2 point diamonds (.005 carats.) The brilliance of our diamonds no matter its color or clarity renders justice to our craftsmanship.

The Magic of Hearts and Arrows

Hearts and ArrowsHearts and Arrows originated in Japan in the late 1980s and arrived in the US in the mid 1990s. When looking at Hearts and Arrows diamonds you can distinguish two things: from the top called the crown, a diamond shows an arrow pattern and when flipped over you see a heart pattern. Thanks to the Hearts and Arrows viewer you can see those lovely kaleidoscopic patterns appear in front of your eyes. This pattern denotes an optically perfect symmetry of facets.

Hearts and Arrows diamonds may have a symmetrical cut, but not all are cut to ideal parameters and not all have optimum light return. The absence of Hearts and Arrows optical symmetry does not mean that a diamond will have less performance, as it is the overall geometry of a diamond that determines its light performance.

At Grunberger diamonds all of our diamonds are Ideal Cut with with Hearts and Arrows. We are the only ones in the diamond trade that sort as small as we do with such precision.

Every diamond we make is Ideal Cut with Hearts and Arrows. This ensures a homogenous make and maximum brilliance. We manufacture over 200,000 diamonds a month that meet this criteria in over 40 qualities: from IF to I-2 and D color to M in color.

As an AGS Supplier we hold tight tolerances for qualities such as color, clarity, and sizes. Our calibrated diamonds can be sorted with precision down to .00250 of a millimeter.

“Our philosophy is to treat our smallest customer as if they were our biggest.”

— David Grunberger

Whether you need 5 diamonds or 50 carats of diamonds, you can place an order by 3:00 PM (Eastern) and it will ship the same day for next-day delivery. This type of service is top tier in the industry across our customer base of retailers, manufacturers, and wholesalers.

All our bench jewelers know the convenience of the Grunberger Precision Cut®. Whether you order 50 diamonds or 50 carats of diamonds, our cut causes each one to have almost identical dimensions and proportions. This saves money during setting, increases production and reliability of finished goods. Grunberger Precision Cut® diamonds are a C.A.D. designer’s dream. Just send us the C.A.D. layout and we ship what fits!

The Grunberger Precision Cut® took years to perfect. During this time we manufactured many of the tools needed for this level of precision, due to the fact that tools of this nature didn’t exist. We are proud to offer you a diamond with such light and fire that it will enhance any jewelry piece. The consistency in cut allows for “no surprise” reliability and quality when it is time to set the diamonds. Once your piece is complete, the homogeneity in our cutting will become one with your creation and maximize the light to its originality.


Because Grunberger Diamonds is an AGS Supplier you will enjoy peace of mind when ordering. Our accuracy in grading allows you to only order what you need. The precision in sorting reduces the need to order more than you can use to ensure you have the sizes needed to complete your piece. Our “no minimums” ordering and same day shipping allow you to get exactly what you need, when you need it, for the last-minute customers who still expect nothing less than perfection.

Our U.S. office is open Monday through Friday from 9 AM to 5 PM Eastern. Our sales team is available both before and after office hours via phone, text, and email. Our goal is to be ready, waiting, and accessible when your need arises.

From C.A.D. layouts to stock inventory, we have the sizes, qualities, quantities, and service you need. Our consistency in cut saves you time and money while ensuring the most brilliant finished piece for your customer.

Learn about the Grunberger Diamond Essentials Program »


For the people that set all the diamonds they buy, here is your dream come true:

  • Every diamond is made proportionally consistent in each and every dimension.
  • Consistency in cut saves you time and money.
  • Our service and shipping you can count on saves you time and money.

All this results in a product that outperforms all others with unmatched beautry and sells faster for a higher profit. Grunberger Precision Cut® gives you more!

Wholesale Buyers

Get what you need by the parcel when you need it, in a quality and consistency your customers will come to expect. When our industry is viewed as a commodity, you can offer something truly different. We are here to make your life easier and your customers more loyal.

Parcel pricing upon request.