Tips to Know Best Quality Gemstones and Accurate Grading System

Colorful, distinctive, and naturally fascinating, gemstones have been treasured for centuries in jewelry, decorative objects, and cultural traditions. But when you are shopping for a gemstone today, beauty alone does not tell you whether a stone is high quality.

Evaluating a colored gemstone requires looking at several factors together, including its color, clarity, cut, carat weight, treatments, origin when relevant, and gemstone type. Just as importantly, buyers should understand that colored gemstones do not have one universal grading system that works exactly like diamond grading.

Whether you are comparing a ruby ring, an emerald necklace, sapphire jewelry, or another colored gemstone, understanding these quality factors can help you make a more informed purchase.

How Can You Tell If a Gemstone Is High Quality?

A high-quality gemstone typically combines attractive color, appropriate clarity for its gemstone variety, a well-proportioned cut, and desirable size without sacrificing beauty or durability. You should also check whether the gemstone is natural or laboratory-grown, whether it has received any treatments, and whether important claims are supported by a reputable gemological laboratory report when appropriate.

There is no single characteristic that determines gemstone quality. For example, a large gemstone is not automatically better than a smaller one, and a gemstone with inclusions is not automatically poor quality. Each factor needs to be considered in the context of the particular gem.

What Determines the Quality of a Gemstone?

The familiar concepts of color, clarity, cut, and carat weight can be useful when evaluating colored gemstones. However, these factors should not be treated as a universal colored-gemstone grading scale. Their importance and interpretation can vary considerably between ruby, emerald, sapphire, and other gemstone varieties.

Quality Factor What to Examine Positive Signs Potential Warning Signs Color Hue, tone, saturation, and color distribution Attractive, well-saturated color appropriate for the gemstone Overly dark, washed-out, or undesirable uneven coloration Clarity Inclusions, transparency, and surface-reaching features Clarity appropriate for the gemstone variety without serious durability concerns Distracting inclusions or fractures that may affect durability Cut Proportions, symmetry, polish, windowing, and extinction Balanced proportions and an attractive face-up appearance Large windows, excessive dark areas, poor symmetry, or weak polish Carat Weight Weight rather than physical dimensions alone Size balanced with overall gemstone quality Paying primarily for weight while sacrificing color, clarity, or cut Treatment Whether and how the gemstone has been enhanced Clear and accurate treatment disclosure Undisclosed or unclear treatment information Laboratory Report Gem identification and disclosed findings A report from a reputable independent gemological laboratory when appropriate Vague or unverifiable "certified gemstone" claims

4 Key Factors for Evaluating Colored Gemstones

1. Color



For many colored gemstones, color is one of the most important quality and value factors. But describing a gemstone simply as "red," "green," or "blue" does not provide enough information.

Gemologists commonly describe color using three important characteristics:

• Hue: The basic impression of color, such as red, green, blue, or a combination of colors.
• Tone: How light or dark the color appears.
• Saturation: The strength or intensity of the color.

A desirable combination depends on the gemstone. Extremely dark stones may lose visible brightness, while overly light stones may lack the color intensity buyers expect from certain gem varieties.

Color distribution also matters. Some gemstones show color zoning, where different areas of the stone display noticeably different concentrations of color. A skilled cutter may orient a gemstone to create a more attractive face-up appearance.

2. Clarity



Gemstone clarity describes the presence and visual impact of internal inclusions and external or surface-reaching features. However, colored gemstones should not all be judged by the same clarity expectations.

Inclusions are natural features that can form as a gemstone develops. Their presence does not automatically mean a gemstone is poor quality.

For example, natural emeralds commonly contain inclusions that may be visible without magnification. Fine rubies and sapphires can also contain inclusions. What matters is how those features affect the gemstone's beauty, transparency, brilliance, and durability.

When examining clarity, ask:

• Are the inclusions visible without magnification?
• Do they noticeably reduce transparency or beauty?
• Are there fractures reaching the gemstone's surface?
• Could any inclusion affect the gemstone's durability?
• Is this type and amount of inclusion normal for the gemstone variety?
• Has the gemstone undergone clarity enhancement?

Therefore, avoid using a simple rule such as "the clearest gemstone is always the best." Clarity needs to be judged in the context of the specific gemstone.

3. Cut



The cut of a gemstone is not the same thing as its shape.

A gemstone's shape describes its outline, such as round, oval, pear, cushion, emerald, marquise, or princess. Its cut quality relates more broadly to factors such as proportions, facet arrangement, symmetry, polish, and how effectively the finished stone displays its color and light.

Popular gemstone shapes and cutting styles include cushion, oval, round, pear, radiant, emerald, and princess. You can learn more about specific styles in our guides to cushion-cut gemstones and princess-cut gemstones.

What Is Windowing in a Gemstone?

Windowing occurs when an area of a transparent gemstone, often near its center, allows you to see through the stone rather than returning an attractive amount of light and color to the viewer. A pronounced window can make a gemstone appear less lively.

What Is Extinction in a Gemstone?

Extinction refers to areas that appear very dark or almost black because little visible light is returned to the viewer. Some dark areas can be normal, but excessive extinction may reduce the gemstone's overall visual appeal.

A well-cut colored gemstone should balance its proportions, color, brilliance, and face-up appearance rather than simply retain as much rough weight as possible.

4. Carat Weight



Carat is a measurement of weight, not a direct measurement of physical size. One carat equals 200 milligrams, or 0.2 grams.

Because different gemstone materials have different densities, two gemstones with the same carat weight can have different physical dimensions. For example, a one-carat ruby and a one-carat emerald do not necessarily appear exactly the same size.

For gemstones of the same variety and comparable quality, larger fine-quality specimens may command higher prices when larger material is rarer. However, carat weight alone does not determine gemstone quality.

Is There a Universal Gemstone Grading System?

No single universal grading system is used to grade all colored gemstones in the same way.

The Gemological Institute of America's well-known 4Cs and clarity grades such as VVS, VS, SI, and I are associated with diamond grading. These diamond clarity grades should not be presented as a universal clarity-grading scale for ruby, emerald, sapphire, and every other colored gemstone.

Colored gemstones are instead evaluated according to characteristics relevant to their particular species and variety. These may include color, transparency, clarity, cut, carat weight, treatments, optical phenomena, and—in some cases—geographic origin.

For additional gemological information, readers can refer to the GIA Gem Encyclopedia.

What Do AAAA, AAA, AA, and A Gemstone Grades Mean?

You may encounter gemstones marketed using letter grades such as AAAA, AAA, AA, and A. These labels can be useful within a seller's own clearly defined quality system, but shoppers should understand an important limitation:

AAAA, AAA, AA, and A are not a universal colored-gemstone grading standard.

The exact criteria can differ between jewelers and gemstone sellers. Therefore, a gemstone described as "AAA" by one seller should not automatically be assumed to be equivalent to an "AAA" gemstone from another.

Rather than relying only on a letter grade, examine the seller's definition and consider:

• Color quality and distribution
• Transparency and clarity
• Cut quality
• Carat weight
• Treatment disclosure
• Natural or laboratory-grown origin
• Supporting gemological report, when appropriate

This provides a more meaningful basis for comparing gemstones than a letter grade alone.

Gemstone Quality Is Different for Every Gem

One of the most important lessons for gemstone buyers is that quality cannot be evaluated identically across every gemstone variety. Ruby, emerald, and sapphire, for example, have different color and clarity expectations.

How to Judge Ruby Quality

Color is a major quality factor for ruby. Fine rubies are generally prized for an attractive, strongly saturated red appearance, while stones that are excessively dark or very light may be less desirable depending on their overall characteristics.

You may encounter the traditional trade term "pigeon's blood" when researching rubies. However, descriptive trade terminology should not replace an evaluation of the gemstone's actual color, transparency, clarity, cut, treatment status, and supporting laboratory information.

Inclusions are also common in natural rubies. Instead of expecting every ruby to be completely inclusion-free, consider whether inclusions significantly affect its appearance, transparency, or durability.

Explore our Ruby Education Guide to learn more about this gemstone, or browse ruby rings to see how ruby is used in fine jewelry.

How to Judge Emerald Quality

Fine emeralds are valued for attractive green color, with hue, tone, and saturation all contributing to their appearance. However, clarity expectations for emeralds differ significantly from those for diamonds.

Natural emeralds commonly contain inclusions, sometimes referred to collectively in the trade as jardin. Eye-visible inclusions can therefore be expected in many natural emeralds.

Rather than rejecting an emerald simply because inclusions are visible, consider how much they affect the stone's transparency, beauty, and structural durability.

Emeralds are also commonly clarity enhanced, so buyers should ask whether an emerald has been treated and, when applicable, the degree or nature of the enhancement.

For more information, explore our Emerald Education Guide.

How to Judge Blue Sapphire Quality

Blue sapphire quality is strongly influenced by color. Attractive blue sapphires are often prized for strong saturation combined with a tone that allows the color to remain vivid rather than appearing excessively dark.

Clarity, cut, treatment, size, and sometimes geographic origin can also affect desirability and value.

Names associated with geographic origin, such as Kashmir, should not be treated as automatic quality grades. Individual gemstones from the same geographic source can differ significantly in quality, and important origin claims should be supported by appropriate gemological evidence when they materially affect a purchase.

Learn more through our Blue Sapphire Education Guide.

Natural vs. Lab-Grown vs. Simulated Gemstones

Understanding what you are actually buying is just as important as evaluating its appearance.

• Natural gemstone: A gemstone formed through natural geological processes.
• Laboratory-grown gemstone: A gemstone produced in a controlled environment with essentially the same chemical composition, crystal structure, and relevant physical properties as its natural counterpart.
• Simulant or imitation: A material that resembles another gemstone in appearance but does not have the same fundamental composition and structure.

These terms should not be used interchangeably. A laboratory-grown ruby, for example, is different from a red imitation material that merely looks similar to ruby.

Always check the product disclosure so you know whether you are purchasing a natural, laboratory-grown, or simulated gemstone.

Do Gemstone Treatments Affect Quality and Value?

Many gemstones available in the jewelry market may be treated to improve their color, clarity, or overall appearance. However, not every gemstone is treated, and treatments vary significantly between gemstone varieties.

Examples of gemstone treatments can include:

• Heat treatment
• Clarity enhancement using oils or resins
• Dyeing
• Coating
• Fracture filling
• Diffusion treatment
• Irradiation in applicable gemstone materials

A treatment does not automatically make a gemstone unsuitable for jewelry. The important issue for consumers is clear disclosure.

Before buying, ask:

• Has this gemstone been treated?
• What type of treatment was used?
• Is the treatment stable under normal wear?
• Does it require special cleaning or care?
• Has the treatment been disclosed in the accompanying documentation?

Treatment information can affect care requirements, rarity, and value, making it an important part of an informed purchase.

Why Does a Gemstone Laboratory Report Matter?

A gemological laboratory report can provide independent information about a gemstone. Depending on the stone and type of report, this may include identification, whether the material is natural or laboratory-grown, detectable treatments, and—in some cases—an opinion about geographic origin.

However, the words "certificate," "certified gemstone," or "gemstone certificate" should not be treated as proof of quality on their own.

When a laboratory report is important to your purchase:

• Check the name of the issuing laboratory.
• Check that the report details correspond to the gemstone.
• Verify the report number through the laboratory when online verification is available.
• Read what the report actually states rather than relying only on the seller's summary.
• Remember that identification does not necessarily equal a quality grade or appraisal value.

How to Check Gemstone Quality When Buying Online

Shopping online makes it impossible to examine a gemstone physically before purchasing, so transparency from the seller becomes particularly important.

Before completing your purchase, check the following:

1. Read the gemstone description carefully. Look for gemstone type, dimensions, carat weight, treatment information, and whether it is natural or laboratory-grown.
2. Examine product images and videos. When available, multiple angles can provide a better understanding of color and appearance.
3. Ask about treatments. Do not assume a gemstone is untreated unless that information is clearly stated and supported where appropriate.
4. Review supporting documentation. For important gemstones, check whether a reputable laboratory report is available.
5. Read the return and exchange policy. Understand the applicable conditions and time limits before purchasing.
6. Check care requirements. Some gemstones and treatments require gentler cleaning methods than others.

For additional shopping advice, read our guide to buying jewelry online.

Gemstone Buying Red Flags to Watch For

A beautiful photograph or impressive quality label should never be the only reason to purchase a gemstone. Be cautious when you encounter:

• Undisclosed treatments: The seller cannot or will not explain whether the gemstone has been treated.
• Undefined AAA or AAAA grades: A quality label is used without explaining the criteria behind it.
• Unclear origin terminology: Geographic origin is used as a quality claim without supporting information.
• Vague "certified" claims: The seller mentions certification without identifying the issuing laboratory or report.
• No natural/lab-grown disclosure: It is unclear whether the gemstone formed naturally or was created in a laboratory.
• Carat weight presented as quality: A larger gemstone is promoted as inherently better without discussing its color, clarity, and cut.
• No treatment information: The product description does not provide enough information to understand possible enhancements.
• Unclear return terms: The return or exchange conditions are difficult to find or understand.

Quick Gemstone Quality Checklist

Before buying a colored gemstone, use this checklist:

• What gemstone species or variety am I buying?
• Is it natural, laboratory-grown, or simulated?
• How attractive are its hue, tone, and saturation?
• Is the color reasonably well distributed?
• Are inclusions visible, and do they affect beauty or transparency?
• Could any fracture or inclusion affect durability?
• Is the gemstone well cut?
• Does it show obvious windowing or excessive extinction?
• What is its carat weight and physical dimensions?
• Has the gemstone received any treatment?
• Are all relevant treatments disclosed?
• Is geographic origin being claimed, and is that claim supported where necessary?
• Is a reputable laboratory report available when appropriate?
• Can the report be verified?
• What are the seller's current return and exchange terms?

Frequently Asked Questions About Gemstone Quality and Grading

What is the most important factor in gemstone quality?

There is no single factor that determines the quality of every gemstone. Color is particularly important for many colored gemstones, but clarity, cut, carat weight, treatments, and gemstone-specific characteristics should also be considered together.

Is AAA or AAAA gemstone quality standardized?

No. Letter grades such as AAAA, AAA, AA, and A are not a universal colored-gemstone grading standard. Sellers may define these categories differently, so buyers should examine the seller's grading criteria and the gemstone's actual characteristics rather than relying on the label alone.

Do gemstones use the same 4Cs as diamonds?

Color, clarity, cut, and carat weight are useful concepts for evaluating many colored gemstones, but the standardized diamond 4Cs grading framework should not be applied to all colored gemstones in exactly the same way. Different gemstone varieties have different quality characteristics and clarity expectations.

Does a gemstone with inclusions have poor quality?

Not necessarily. Many natural colored gemstones commonly contain inclusions. Emeralds, rubies, and sapphires can all contain natural internal features. What matters is the type, location, visibility, and effect of those inclusions on appearance, transparency, and durability.

Are treated gemstones considered real gemstones?

A natural gemstone does not stop being natural simply because it has received an accepted treatment, but the treatment should be disclosed. Treatments can affect appearance, care requirements, rarity, and value, so buyers should understand what enhancement has been performed.

Is a bigger gemstone always more valuable?

No. Carat measures weight rather than overall quality. A smaller gemstone with exceptional color, clarity, and cut can be more desirable than a larger stone with weaker overall characteristics. For gemstones of comparable quality and the same variety, rarity at larger sizes can influence price.

Does a gemstone need a laboratory report?

Not every gemstone purchase requires a laboratory report. However, independent gemological documentation can be particularly useful for significant purchases or when natural versus laboratory-grown origin, treatments, or geographic origin materially affect the buying decision.

How can I check gemstone quality when shopping online?

Review the gemstone's color, dimensions, carat weight, treatment disclosure, natural or laboratory-grown status, images or videos, available laboratory documentation, and the seller's return policy. Avoid making a decision solely from an AAA or AAAA label.

Choose a Gemstone Based on More Than a Grade

The best way to evaluate a gemstone is to look beyond a single grade or label. Color, clarity, cut, carat weight, treatment status, gemstone type, and reliable disclosure all work together to help determine whether a stone is right for you.

Most importantly, remember that different gemstones should be judged according to their own characteristics. The inclusions commonly seen in emerald, for example, should not be evaluated using the same expectations applied to diamond. Likewise, commercial labels such as AAA or AAAA only become useful when the seller clearly explains what those grades mean.

By learning these fundamentals and asking the right questions, you can compare gemstones more confidently and choose jewelry based on meaningful quality information rather than marketing terminology alone.