Gem Lab Denver Colorado

American Gem Registry utilizes a fully equipped gem lab in order to accurately identify and class diamonds and colored gem stones.

Gem Lab Equipment

We have a massive gem lab equipment inventory including the following tools and instruments:

gem lab coloradoBinocular and trinocular Microscopes, the work horse of the gem lab

Gem Lab Denver

A.D. Leveridge gauge

gem labPresidium micrometer

gem lab diamond master set
GIA & AGS certified diamond color master comparison stones, an integral part of the gem lab

gem lab denverMettler scale

Prismatic Spectroscope
Verneil slide gauge
Metal testing acids
Chelsea & Hanneman Optic Filters
Thermal conductivity probe
Duplex II refractometer
Long and Shortwave UV lighting
Macro and micro photographic equipment
Sarine Diascan measurement system
GemDialogue color grading system
Kee metal testing
Gemprint system
Synthetic diamond screener
Hearts & Arrows viewer
DiamCalc raytracing system
AGS ASET proportion system.

Role of the Gem Lab

Get a fair deal

The role of the Gem Lab in appraisal is to precisely quantify the type and quality of stones.

Most jewelry appraisals are for insurance replacement purposes. This means that the value conclusion is the appraiser’s estimation of the appropriate funding to allow the insurance company to replace the item with a new one of like kind and quality, at retail, in the case of a loss In order to accomplish this, your insurance company is likely to require a appraisal services by an accredited gem lab before they bind the policy. What the insurance company wants is a clear definition of ‘like kind and quality’ so that they can properly process a claim and accurately replace the property in the case of a loss. As long as the bottom line is at least as much as they will be required to spend, they are going to be happy with the number since the premium they will be collecting is a direct percentage of this bottom line number.

Most insurance companies will not issue a payment for the bottom line amount of your appraisal in the case of a loss!

Instead, they will replace the lost item with one that matches the description in the appraisal. The insurance companies are pretty good shoppers and they drive a pretty hard bargain. They are going to pay the least they possibly can while still upholding the terms of their contract. In no way is this cheating or being unfair to their policyholders, it’s just good business.

Gem Lab in Valuation

Keep it real

Our Gem Lab is equipped to the highest standard in order to identify, grade and determine Fair Market Value.

(FMV) is a legally defined term and the definition changes slightly between the various jurisdictions and courts. If you need a FMV appraisal, check your local jurisdiction to make sure that the correct rules and markets are being applied.

For federal tax purposes, fair market value is the following:

The most probable price at which property would change hands between an willing buyer and a willing seller, neither being under any compulsion to buy or to sell, both having a reasonable knowledge of all relevant facts, and with the sale being made to the public in the most relevant market taking into consideration the location of the property.

FMV appraisal services are usually done for tax related purposes by an accredited gem lab.
They can be tricky and the jewelry store style of appraisers are not prepared to properly complete one.
Our ISA trained appraiser can do FMV work for you our your clients and get it right the first time.
We are fully USPAP compliant and are happy to work either directly with the client or through their attorneys.

The Gem Lab helps you financially!

Inflated appraisals are no problem for the insurance company. If the value on the appraisal is too high, their behavior in the case of a loss will be unchanged, they will replace with like kind and quality. The only difference is the premium that they get to collect since your premium is a direct percentage of the appraisal value after all. The parties who gain by an inflated appraisal are the insurer from the higher premium; and the retailer in ehhancing the ease of sale. If they can tell you that your ring is ‘worth’ two or three times what you are paying, it makes them look good. This isn’t an appraisal service, it’s an advertisement! It’s no wonder it’s free

Diamond Grading

diamond color grading

The Gem Lab establishes a precise grade of your stone.

Much of the value of your new diamond is going to be based on the 'grade' of the stone.
This is a ranking of your stone relative to other diamonds that you may have seen. A better stone will bring a higher price. For this reason, the grade of the stone turns out to be a terribly important issue. Although it is a bit complicated, the basic ideas are pretty simple.

Back in the 30's a non-profit group called The Gemological Institute of America was formed to standardize the way diamonds were graded and to train people to grade them that way. Before GIA, diamonds were assigned grades like "Top Wesselton" and "Cape" that were based on the mine of origin. Even those in the industry were confused when the traded amongst themselves. The GIA divided the grading into 4 categories that they called the 4C's; Carat Weight, Clarity, Color; and Cut. In particular, Clarity and Color were assigned their own special scales that are still known as the GIA grading scale. The GIA has a division called the Gem Trade Laboratory (GTL) that offers grading reports on individual diamonds. These reports are popularly known as 'GIA Certificates'. These certificates, or others like them, accompany most major stones that you will see.


Click here to learn more about GIA

The people trained by the GIA to grade stones are called gemologists. This is a specific designation from the GIA School to indicate someone who has completed that program. 'Graduate Gemologist' is the top designation from the GIA in their gemological program and will be designated in documents with initials G.G. after a name. There are several other agencies that compete with GIA for gemological training and give different designations. The Gemmological Association of Great Britain, for example, issues F.G.A..

Since then, the GIA has become huge. Their lab is the dominant brand name in diamonds. They just moved to a lovely new campus in Carlsbad California and, despite their non-profit status seems to be rolling in money. This has given rise to competitors. Grading certificates are offered by at least a dozen companies throughout the world and gemological training is available from at least 5 that I know of. They all describe the basic information about the stone and often they often add a few things that are just their own. For the most part, they all use the GIA method for grading clarity and color. These scales are explained individually under their respective sections of this document with links to each in the left margin.

Please notice that the chapters about the 4C's actually contain 6C's. There are probably more but I have to stop somewhere.


Color in diamonds is caused by trace chemicals occurring in the earth where the rough crystals formed over millions of years.

D-Z Color Range
Most diamonds are graded using the GIA developed D-Z color grading scale where D is at the top, Z is notably yellow or brownish, and the letters in-between descend very gradually. DEF are considered colorless and GHIJ are considered near-colorless. The colorless and near-colorless ranges are the most popular among diamond buyers as the differences are extremely subtle. Below J, diamonds show progressive levels of “warmth” seen as a yellow or brownish tint.

Fancy Colored Diamonds
A small percentage of diamonds with more color saturation than Z are called “Fancy Colored Diamonds,” or FCDs. Yellow or brown FCDs run from light to vivid. Additionally, FCDs may be an altogether different color like pink or blue. All Fancy Colored Diamonds are graded using a different scale and approach than diamonds in the normal D-Z range.

Grading Color
Diamonds in the normal D-Z range are graded face-down, viewed through the side of the pavilion. This is because shape and cut quality both influence how light gets in and out of the diamond. Grading face-down allows for a neutral assessment of body color. The descending grades from D to Z are very gradual.

Significant Differences
The result of face-down grading is the fact that several diamonds of same-grade can appear different colors when viewed face-up. This can be influenced by several factors, including the following:

Laboratory Standards: Different laboratories have slightly different standards for color. Please see the page on Grading Laboratories for more information.

Shape: Brilliant cutting styles return light to the viewer more efficiently than step cuts, so a round brilliant may show less apparent colour face-up than an emerald or Asscher of the same grade.

Fluorescence: A diamond in the near-colorless or faint yellow range may have it’s face-up colour reduced by medium or stronger blue-fluorescence. This is only seen on a case-by-case basis.

Cut-Quality: A diamond cut with the critical angles and precision needed for highest performance have shorter ray-paths reducing their face-up colour; in some cases by multiple grades.

Color and cutting are related.
The finest cut round brilliants often face up with less color than the laboratory colour grade they were assigned, which was determined face-down. Why? Because light gets in and out of the diamond faster, on shorter ray-paths. This is the opposite with poor cutting, where critical angles are missed and light rays either escape through the pavilion or make multiple bounces before leaving, illuminating body tone. Poorly cut stones can face up noticeably darker.

Call our appraiser today at (303)223-4944 for an appointment or inquire right now by email



The cut of a diamond refers to everything man has done in the process of converting it from a piece of rough, natural diamond material into a finished gemstone capable of the beautiful brightness and sparkle which makes diamonds the most popular of all precious gems. The details of cut include shape, make, angles, proportions, optical precision, weight ratio, facet symmetry and final polish. These specifics all combine to determine how the diamond will appear as it travels through the world’s many lighting conditions.

Most Important. Least Discussed.
Although geometry is the most important component for diamond beauty, it’s typically discussed far less than color and clarity in most places. One reason is that color and clarity grading are easily learned by new sales professionals. But understanding the many details of optics requires a stronger commitment, as well as foundations in geometry and physics. It’s worth noting that most diamonds are made to average quality and in-depth discussions about geometry would reveal that lack of quality in average stores. The fact that many grading labs include little or no information about the make only underscores the resistance to education felt in commercial markets.

Top Cut -Improves All.

Diamonds in the top few percent of the world’s cut actually improve in the other Cs: They appear larger for their carat weight, face up more colorless and clarity characteristics can be less visible. Most importantly, they explode with dazzling whiteness and rainbow colors, even away from jewelry store lighting where most diamonds go dark.

 Helps Size Appearance:
A diamond designed for the highest level of visual performance appears larger than diamonds of average cut quality because they are bright all the way from edge-to-edge, not just bright in the center.

 Helps Color:
A diamond with the critical angles and precision needed for highest performance has shorter ray-paths reducing face-up color; in some cases by multiple grades.

Helps Clarity:
A diamond planned for highest performance boasts superior brightness and scintillation, even when removed from jewelry store lighting, which helps to “mask” inclusions.

Laboratory Standards: Different laboratories have radically different standards.  Please see our page on Grading Laboratories for more information.

Shape: Brilliant and mixed shapes like round brilliant, princess and cushion, have a different “flavor” than step cuts such as emerald and asscher.



Nearly all diamonds have natural characteristics that formed within the rough crystal over millions of years of growth. Most are microscopic and need magnification to detect. Others may be visible to the naked eye.

Absolutely Unique

What is certain is that no two diamonds are the same. Each is like a snowflake; never repeated in nature. In fact, one sure way to identify your diamond is to learn where a primary inclusion lies. Depending on the diamond’s clarity specifics – and your eyesight – it may be possible with no aid, or it may require a magnifying device. Either way, every diamond’s inclusions tell a special story that is absolutely unique.

Blemishes and Inclusions

Clarity characteristics are separated into two broad categories: Blemishes, which are external, and Inclusions, which are internal. The laboratory grading report will list all characteristics, in order of importance, with the primary characteristic(s) “setting” the clarity grade.

Grading Clarity

The clarity grade is determined by examining the diamond face-up at 10X magnification in neutral lighting. Five factors are considered: These include the size, number, position, visibility and type of characteristics visible at 10X magnification. If the implications are minute or minor the clarity grade is likely to be high. If the implications are noticeable or obvious the clarity grade will be lower.

  • When strictly graded, FL and IF indicate the diamond is Flawless, or Internally Flawless; revealing no inclusions at this magnification.
  • VVS1 and VVS2 indicate Very Very Slight inclusions; meaning that only minute characteristics were detected.
  • VS1 and VS2 imply Very Slight inclusions; the grader saw only minor characteristics.
  • SI1 and SI2 grades indicate the diamond was Slightly Included; inclusions were notable under 10X magnification.
  • I1 means Included; characteristics were obvious to the grader when magnified
  • .The I2 and I3 grades are reserved for diamonds with extremely obvious inclusions and/or durability issues caused by the inclusion type.

Naked-Eye Appearance

While diamonds are graded under 10X magnification they are not graded outside the ‘scope. This means that several diamonds of same-grade can appear differently to the naked eye. This is further influenced by several factors, including the following:
Laboratory Standards: Different laboratories have slightly different standards for clarity.
Shape: Brilliant cutting styles have greater faceting complexity and less transparency, so a round brilliant may show inclusions less than an emerald or Asscher of the same grade.
Size and Number:An inclusion plot that looks “clean” may not correspond to a cleaner presentation, since a single grade-setting crystal may be more naked-eye visible than several smaller crystals which set the same clarity grade collectively.

Position and Visibility: A diamond with a dark central inclusion can present with far more naked-eye visibility than one with a transparent inclusion under a girdle facet, yet both diamonds might have the same clarity grade.
Cut-Quality: A diamond cut with the critical angles and precision needed for highest performance boast superior brightness and scintillation, even when removed from jewelry store lighting, which helps to “mask” inclusions.
Cut quality affects visible clarity

Carat weight


Diamond weight is expressed in carats. Carats are further divided into 100 “points” so that a 0.90 ct diamond may be called a 90-pointer, a 0.88 carat diamond an 88-pointer and so on. The word ‘carat’ has roots in ancient times, when diamonds were compared against carob beans by traders in the Ottoman Empire.

Buyer Beware

Carat weight is NOT size. Diamonds with the same carat weight can have smaller or larger vertical spreads, depending on the geometry of their cut. This is no different than two people weighing the same, but one is taller and the other is wider.


Shallow and Deep Diamonds

Carat weight influences price more than any other factor so the goal of mass-manufacturers of diamonds will always be keeping as much weight from the rough crystal in the diamond as possible. This is even more important than the beauty of the final product since bigger diamonds bring bigger money. The result is millions of diamonds on the market which sparkle under bright lights (all diamonds do) but have average performance in normal lighting.

Fine Make Diamonds

Diamonds cut with a goal of beauty and high performance are proportionate, with critical angles and precision-cutting that will promote the best brightness, dispersion and scintillation, even in normal and romantic lighting. Such high performing diamonds appear larger than diamonds of normal cut quality because they have edge-to-edge brightness, not just a bright center. Because it costs more to fine-tune the rough to this degree of beauty, these diamonds are far more rare than shallow and deep diamonds and cost a bit more.


The example above, with a spread of 6.30 millimetres was cut slightly “deep” and will look smaller than a proportionate one-ct diamond, spreading closer to 6.50 mm. The example on the left above has greater spread, but was cut “shallow” and will lack the critical angles necessary for performance, reducing edge-to-edge brightness and potentially increasing dark zones.

Carat Weight and Laboratory Grading

Carat weight is standardized and repeatable around the world. What is not repeatable is the assessment of whether a diamond is too shallow or deep to promote optimum light return.

A skilled diamond cutter can plan the “lay” of a grade-setting inclusion to reduce its face-up visibility. It may be impossible to omit a primary characteristic (and the resulting clarity grade) but a skilled cutter can orient the rough so that they become transparent or less visible. This is particularly true for SI1, SI2 and I1 clarity grades.