Jewelry Certification & Valuation

Understanding the AGS Laboratory and Its Impact on Jewelry Valuation

In the world of fine jewelry and gemstones, trust and transparency are paramount. When purchasing a significant diamond or gemstone, understanding its quality, origin, and authenticity is crucial. This is where independent gemological laboratories play a vital role. Among the most respected is the AGS Laboratory, operated by the American Gem Society. This document delves into what the AGS Laboratory is, its grading standards, and how it influences the jewelry market.

Definition

The AGS Laboratory is a premier gemological grading facility that operates under the umbrella of the American Gem Society (AGS). It is renowned for its rigorous and objective grading of diamonds and, to a lesser extent, colored gemstones. The AGS Laboratory is distinguished by its commitment to scientific precision, ethical standards, and a comprehensive approach to grading that goes beyond the traditional 4Cs (Carat, Cut, Color, Clarity), particularly emphasizing the importance of cut quality.

Key Features

The AGS Laboratory is recognized for several key features that set it apart:

Comprehensive Grading: While it adheres to the 4Cs, the AGS grading system offers a more detailed analysis, especially concerning cut.
Advanced Technology: The laboratory employs state-of-the-art equipment and sophisticated methodologies to ensure accuracy and consistency in its grading reports.
Focus on Cut: The AGS is particularly lauded for its groundbreaking work in cut grading. Its system evaluates not just the dimensions but also the light performance, brilliance, fire, and sparkle of a diamond, providing a more holistic view of its beauty.
Industry Leadership: Through its research and development, the AGS Laboratory has significantly contributed to the understanding and standardization of diamond cut quality.
Independent and Unbiased: As an independent entity, the AGS Laboratory provides objective assessments, free from the influence of manufacturers or retailers.
Consumer Focus: The AGS aims to empower consumers with reliable information, enabling them to make informed purchasing decisions.

Origin and History

The American Gem Society (AGS) was founded in 1934 by a group of independent jewelers who sought to establish a higher standard of ethical conduct and professional expertise within the jewelry industry. The AGS Laboratory was established later, building upon the Society’s foundational principles. Its development was significantly driven by the need for a more precise and scientific method to evaluate diamond cut, an aspect that traditional grading systems often treated with less emphasis. The AGS Laboratory has consistently invested in research, particularly in the area of diamond optics, to develop its advanced cut grading system.

Types / Variations

The primary focus of the AGS Laboratory is the grading of diamonds. Their reports typically cover:

Round Brilliant Diamonds: The AGS is most famous for its highly detailed grading of round brilliant cuts, where their cut grading system truly shines.
Other Diamond Shapes: While less prominent than for round brilliants, the AGS also grades other diamond shapes (fancy cuts) such as princess, oval, emerald, pear, and marquise. The evaluation of cut for these shapes is adapted to their specific faceting patterns and optical characteristics.

While diamonds are their main area of expertise, the AGS Laboratory also provides services related to colored gemstones, including identification and grading of quality characteristics, though this is less emphasized than their diamond services.

How It's Made (Grading Process)

The grading process at the AGS Laboratory is meticulous and multi-faceted, involving several highly trained gemologists and advanced technology. For diamonds, the process typically includes:

Initial Inspection: A preliminary examination to identify the stone and note any obvious characteristics.
Proportion Analysis: Using specialized instruments, the precise dimensions and angles of the diamond’s facets are measured. This is critical for the cut grade.
Clarity Grading: Gemologists examine the diamond under magnification (typically 10x) to identify and plot internal inclusions and external blemishes.
Color Grading: Diamonds are graded against a master set of comparison stones in a controlled lighting environment to determine their colorlessness or hue.
Cut Grading: This is a signature component of AGS grading. It involves analyzing proportions, evaluating light performance (brilliance, fire, sparkle) using advanced photometric equipment, and assessing symmetry and polish. The AGS Light Performance® score is a key output.
Carat Weight Determination: The diamond’s weight is precisely measured.
Final Review: The diamond and its accompanying report are reviewed by multiple senior graders to ensure accuracy and consistency.

Each diamond graded by the AGS receives a detailed report that includes all these parameters, often with accompanying diagrams and scores.

Grading & Quality Standards

The AGS Laboratory uses a unique 0-10 grading scale, which differs from the more common alphabetical scales used by some other labs. This numerical scale provides finer distinctions in quality.

Clarity Scale: Ranges from 0 (Flawless) to 10 (Included).
Color Scale: Ranges from 0 (Colorless) to 10 (Light Yellow/Brown).
Cut Scale: This is where the AGS truly innovates. It grades cut on a scale from 0 to 10, with 0 reflecting the highest level of light performance, brilliance, fire, and sparkle. The AGS Light Performance® score is a critical part of this, evaluating how well the diamond returns light.
Polish and Symmetry: These are also graded, contributing to the overall assessment.

The combination of these grades results in an overall diamond grade. The AGS grading system is widely respected for its scientific rigor and emphasis on how a diamond actually looks and performs when worn.

Buying Guide

When considering a diamond graded by the AGS Laboratory, here’s what buyers should look for:

The AGS Report: Always obtain and review the official AGS grading report for the diamond.
Cut Grade: Pay close attention to the cut grade. For AGS, grades of 0, 1, or 2 generally represent exceptional to excellent cut quality and light performance.
Light Performance: The AGS Light Performance® score is a key indicator of a diamond’s beauty and sparkle. Higher scores (closer to 0) are desirable.
Clarity and Color Grades: Understand where the diamond falls on these scales and how it aligns with your preferences and budget.
Proportions: The report often details key proportions like table percentage, depth percentage, and pavilion angles, which contribute to the cut quality.
Laser Inscription: Many AGS-graded diamonds have their report number laser-inscribed on the diamond’s girdle for easy identification and verification.
Compare Reports: If comparing diamonds graded by different labs, understand the nuances of each system. A diamond with an excellent cut grade from AGS might perform differently than one with a similar grade from another lab, due to the AGS’s emphasis on light performance.

Price Range & Value Factors

Diamonds graded by the AGS Laboratory typically command strong prices, reflecting the rigor and reputation of the lab. The value is influenced by several factors:

The 4Cs: As with any diamond, carat weight, color, clarity, and cut are primary value drivers.
AGS Cut Grade and Light Performance: A diamond with an AGS cut grade of 0 or 1, and a high Light Performance score, will generally be more valuable than a diamond with a lower cut grade, even if other characteristics are similar. This is because superior cut directly impacts beauty.
Rarity: Exceptional combinations of the 4Cs, especially high color and clarity in larger stones, increase rarity and value.
Market Demand: General market trends and demand for certain diamond characteristics also play a role.
Retailer Markup: The final price will also include the retailer’s markup, which can vary significantly.

Diamonds graded by AGS are often found in higher-end jewelry stores and with online retailers specializing in quality diamonds, where transparency and superior cut are emphasized.

Care and Maintenance

The grading report from the AGS Laboratory pertains to the diamond’s inherent qualities and does not directly influence its care. General diamond care practices apply:

Regular Cleaning: Clean diamonds periodically with a soft brush, warm water, and a mild dish soap. Avoid harsh chemicals.
Professional Inspection: Have your jewelry checked by a professional jeweler annually to ensure the setting is secure and the diamond is free from damage.
Storage: Store diamonds separately from other jewelry to prevent scratching.
Avoid Harsh Conditions: Remove diamond jewelry when engaging in strenuous activities, swimming, or using cleaning products.

Pros and Cons

Pros:

Highly Respected and Reliable: The AGS Laboratory is known for its accuracy, consistency, and integrity.
Superior Cut Grading: Its detailed evaluation of cut and light performance is unparalleled, providing consumers with a deeper understanding of a diamond’s beauty.
Consumer Empowerment: The comprehensive reports help buyers make informed decisions.
Scientific Approach: Relies on advanced technology and objective measurements.
Numerical Scale: The 0-10 scale offers finer distinctions than some other grading systems.

Cons:

Less Common Than Some Labs: While highly reputable, AGS reports may be less frequently encountered than those from some other major labs, potentially affecting immediate resale liquidity in some markets.
Higher Price Point: Diamonds graded by AGS, especially those with top cut grades, may come at a premium due to their superior quality and the lab’s reputation.
Focus on Round Brilliants: While they grade other shapes, their most innovative grading is for round brilliants, meaning the detailed cut analysis might be less pronounced for fancy shapes compared to rounds.

Common Misconceptions

AGS = Higher Price: While AGS-graded diamonds with top grades are valuable, the grading itself doesn't arbitrarily inflate prices. The higher value reflects the superior quality and beauty captured by the rigorous grading.
All AGS Diamonds are Perfect: The AGS scale allows for a wide range of grades. A diamond graded ‘8’ for clarity, for instance, has visible inclusions. Consumers must understand the specific grades on the report.
Cut Grade is the Only Factor: While AGS emphasizes cut, color and clarity are still critical factors influencing a diamond’s appearance and value. A visually stunning cut cannot compensate for extreme color or very obvious inclusions if those are important to the buyer.
AGS is the Same as GIA: While both are highly respected labs, they use different grading scales and have different emphases. GIA’s alphabetical scale is more widely known, while AGS’s numerical scale and detailed cut analysis are its distinguishing features.

Related Terms

American Gem Society (AGS): The parent organization of the AGS Laboratory.
4Cs: Carat, Cut, Color, Clarity – the fundamental characteristics of a diamond.
Diamond Cut Grade: The evaluation of a diamond’s proportions, symmetry, and polish, impacting its brilliance, fire, and sparkle.
Light Performance: A key metric in AGS grading, assessing how a diamond returns light.
Gemological Institute of America (GIA): Another major independent gemological laboratory.
AGS Light Performance®: The specific scoring system used by AGS to measure a diamond’s light return.

FAQs

What does an AGS report tell me?

An AGS report provides a detailed, objective assessment of a diamond’s quality, including its carat weight, color grade, clarity grade, cut grade, polish, symmetry, and often a measure of its light performance. It serves as a verification of the diamond’s characteristics.

Is an AGS-graded diamond better than a GIA-graded diamond?

Neither lab is definitively ‘better’. Both are highly reputable. AGS is particularly known for its detailed cut grading and numerical scale, while GIA is widely recognized and its alphabetical scale is more familiar. The ‘better’ diamond depends on your priorities; if exceptional light performance is key, AGS may offer more detailed insight.

How much more expensive are AGS-graded diamonds?

Diamonds graded by AGS, especially those with top cut grades (0, 1, 2), are often priced at a premium. This reflects the superior quality indicated by the rigorous grading and the diamond’s superior beauty and sparkle.

Can I trust an AGS report?

Yes, the AGS Laboratory is considered one of the most trustworthy and scientifically advanced gemological grading facilities in the world. Their reports are known for their accuracy and consistency.

What is the best cut grade from AGS?

The AGS uses a numerical scale where 0 represents the highest quality. Therefore, a cut grade of 0 is the best, indicating exceptional proportions and light performance. Grades 1 and 2 are also considered excellent.