Gemstone Clarity: Inclusions, Transparency and Value

Gemstone clarity describes the presence and appearance of internal inclusions and external surface characteristics. These features can affect a gemstone’s transparency, brilliance, durability and value.

Clarity expectations are not the same for every gemstone. Fine aquamarine is normally expected to appear clean to the unaided eye, while natural emeralds commonly contain visible inclusions and fractures. A clarity characteristic that substantially reduces the value of one gemstone may be accepted in another.

For this reason, colored gemstones should not be judged using diamond clarity expectations. Each gemstone variety must be evaluated according to its own natural characteristics, rarity and appearance.

What Are Gemstone Inclusions?

Inclusions are internal features enclosed within a gemstone or extending into it from the surface. They may form while the crystal is growing or develop later through geological pressure, heat and movement.

Common gemstone inclusions include:

• Mineral crystals
• Needles and fine fibers
• Gas bubbles
• Liquid-filled cavities
• Two-phase or three-phase inclusions
• Growth tubes
• Internal graining
• Partially healed fractures
• Clouds of microscopic particles
• Fingerprint-like patterns
• Color-producing particles
• Surface-reaching fractures

External characteristics are usually described as blemishes rather than inclusions. These may include scratches, pits, abrasions, chips, polishing lines and extra facets.

The effect of an inclusion depends on its size, number, location, visibility and contrast with the surrounding gemstone.

What Does Eye-Clean Mean?

An eye-clean gemstone has no inclusions that are easily visible to the unaided eye when viewed under ordinary conditions.

The term is useful but not completely standardized. Whether a stone appears eye-clean may depend on:

• Viewing distance
• Lighting conditions
• The observer’s eyesight
• The gemstone’s size
• Whether the stone is examined face-up or from the side
• The color and contrast of the inclusion
• Whether the gemstone is loose or mounted

A small inclusion visible only through the pavilion may be concealed once the stone is set. An inclusion directly beneath the table can be more noticeable because it occupies a prominent viewing area.

Eye-clean does not mean flawless. A gemstone may appear completely clean without magnification while containing numerous microscopic internal features.

Colored Gemstone Clarity Is Not Graded Like Diamond Clarity

Diamond clarity is commonly graded under controlled conditions using a standardized scale ranging from Flawless to Included.

Colored gemstones do not share one universally accepted clarity grading scale. Their inclusions and transparency vary too greatly among different mineral species and varieties.

A commercial seller may use terms such as eye-clean, slightly included, moderately included or heavily included, but these descriptions can be subjective. They should not be presented as though they were equivalent to standardized diamond clarity grades.

The most practical questions are:

• Are the inclusions visible without magnification?
• Do they reduce transparency or brightness?
• Do they distract from the gemstone’s color?
• Could they affect durability?
• Are they typical for this gemstone variety?
• Has the stone been treated to make fractures less visible?

How Inclusions Affect Appearance

Inclusions can interfere with the passage of light through a gemstone. Large, dark or numerous inclusions may reduce transparency and make a stone look cloudy, dull or uneven.

Location is particularly important. An inclusion beneath the table may be more noticeable than one near the girdle. Dark crystals can attract attention more readily than low-contrast inclusions that blend into the gemstone’s color.

The effect should be evaluated face-up because this is how the gemstone will normally be seen in jewelry. A stone can contain several inclusions and still look beautiful if they do not interfere with its color, brightness or overall character.

Clarity should therefore be considered together with gemstone color and cut rather than treated as an isolated characteristic.

When Inclusions Add Beauty or Interest

Not every inclusion is undesirable. Certain inclusions create valuable optical effects or contribute to a gemstone’s distinctive appearance.

Fine needle-like inclusions can produce a star in properly cut star sapphire or star ruby. Parallel fibers or tubes may create the narrow reflected line seen in cat’s-eye gemstones.

Microscopic particles can scatter light and produce a soft or velvety appearance. Some collectors also appreciate visible crystals, growth patterns and other inclusions as miniature records of a gemstone’s geological formation.

Included gemstones may be cut as cabochons, beads, carvings or crystal slices when transparency is less important than color, pattern or character.

An attractive inclusion pattern should still be distinguished from a fracture that threatens durability.

Inclusions and Gemstone Durability

Clarity is not only an appearance consideration. Certain inclusions can weaken a gemstone or make it more vulnerable during setting, repair or everyday wear.

Potential durability concerns include:

• Large surface-reaching fractures
• Fractures extending through a significant portion of the stone
• Chips along the girdle
• Cavities near prongs
• Inclusions beneath exposed corners or points
• Fractures located where pressure will be applied during setting
• Heavily included areas that respond poorly to heat or ultrasonic cleaning

A small crystal inclusion enclosed safely inside a gemstone may have little effect on durability. A thin fracture extending to the surface can be more concerning even if it is less visually obvious.

The setting should be designed around the actual stone. Vulnerable corners may need V-shaped prongs, a bezel or another protective element. A jeweler must also examine the stone before resizing or repairing jewelry because heat and vibration can affect heavily included or treated gemstones.

Clarity Expectations for Different Gemstones

Every gemstone variety has different clarity expectations. The following comparisons provide practical guidance, but individual stones must still be evaluated separately.

Aquamarine

Faceted aquamarines are generally expected to be eye-clean. Most fine material has high transparency and few visible inclusions.

An aquamarine with obvious inclusions will usually be less valuable than a similarly colored eye-clean stone unless its inclusions create an intentional artistic appearance.

Because clean aquamarine is readily available, there is usually little reason to accept prominent fractures in an ordinary faceted stone.

Morganite

Faceted morganite is also commonly eye-clean. Visible inclusions become more likely in very large stones, but attractive material should generally have good transparency.

Numerous inclusions can reduce brilliance and make pale morganite appear washed out or cloudy. More heavily included material may be carved or fashioned as cabochons.

Tanzanite

Most faceted tanzanite offered for fine jewelry is expected to be eye-clean. Visible inclusions can substantially affect value because clean material is generally available.

Any fractures should also be considered carefully because tanzanite has perfect cleavage and is more vulnerable to impact than sapphire or ruby.

Topaz

Faceted topaz is commonly available with excellent clarity. Eye-visible inclusions are usually undesirable in standard blue or colorless topaz.

Rare colors and unusual natural material may be evaluated differently, but significant fractures remain a durability concern because topaz has perfect cleavage.

Emerald

Natural emeralds commonly contain inclusions and surface-reaching fractures. These features are often described collectively in the trade as the emerald’s jardin, from the French word for garden.

Visible inclusions do not automatically make an emerald unattractive or poor quality. The finest stones still possess strong color, good transparency and a lively appearance.

Clarity becomes a serious problem when inclusions make the stone excessively cloudy or fractures threaten its durability. Because emeralds are frequently clarity enhanced with oil or resin, buyers should understand both the degree of enhancement and any special care requirements.

Ruby

Most natural rubies contain inclusions. Fine ruby is valued primarily for attractive red color, but clarity still matters when inclusions reduce transparency or interfere with brightness.

Large dark crystals, dense clouds or prominent fractures beneath the table can substantially lower value. Surface-reaching fractures may also create durability concerns.

Completely inclusion-free natural ruby should be examined carefully because synthetic ruby is widely produced. Absence of visible inclusions does not prove that a stone is synthetic, but important stones should be supported by an independent laboratory report.

Sapphire

Blue sapphires commonly contain inclusions but generally tend to have better clarity than rubies.

Typical features can include mineral crystals, needles, clouds, color zoning and partially healed fractures. Fine rutile needles known as silk can sometimes contribute to a desirable velvety appearance. When densely and properly oriented, similar inclusions may produce a star effect in a cabochon sapphire.

The best sapphire is not necessarily the cleanest stone under magnification. Strong color, transparency and an attractive face-up appearance are usually more important than microscopic perfection.

Spinel

Fine spinel is often transparent and may appear eye-clean, although natural inclusions are common.

Prominent fractures or dark inclusions can reduce beauty and value. High-quality red, pink, cobalt-blue and other rare colors may command substantial prices even when minor inclusions are present.

Synthetic spinel is also widely available, so clarity alone should never be used to determine natural origin.

Garnet

Clarity expectations vary across the garnet family. Red almandine, pyrope and rhodolite garnets are often available without obvious eye-visible inclusions.

Orange spessartine and hessonite garnets more commonly display visible internal characteristics. Hessonite may show a distinctive roiled or heat-wave-like appearance.

Demantoid garnet may contain fine radiating fibers known as horsetail inclusions. Well-formed horsetails can be desirable to collectors and may support identification, although they are not present in every demantoid.

Tourmaline

Tourmaline clarity varies considerably with color and variety. Green tourmaline is often available with good clarity, while pink and red tourmalines are more frequently included.

Some rubellite contains fractures and liquid inclusions that are accepted when the stone has strong, attractive color. However, heavily fractured tourmaline may be vulnerable during setting or everyday wear.

Copper-bearing Paraíba-type tourmaline is rare enough that visible inclusions may be accepted when the color is exceptional.

Opal

Opal is normally evaluated differently from transparent faceted gemstones. Its value depends heavily on body color, pattern, brightness and play-of-color.

Internal features, fractures, crazing and inclusions can still affect durability and value. Crazing consists of fine cracks and can indicate instability. It should not be confused with a harmless color pattern.

Dark inclusions may also interrupt play-of-color or become distracting in transparent and translucent opal.

Do Inclusions Prove That a Gemstone Is Natural?

Inclusions can provide valuable evidence about a gemstone’s identity, formation, treatment and possible origin. Gemologists study them using magnification and other instruments.

However, visible inclusions alone do not guarantee natural origin. Laboratory-grown gemstones can contain inclusions produced during the growth process, and some may resemble features found in natural stones.

Likewise, an exceptionally clean gemstone is not automatically laboratory-grown. Certain natural gemstones commonly occur with high clarity.

A reliable determination may require microscopic examination, spectroscopy, chemical analysis and other laboratory testing.

Clarity Enhancements

Some gemstones are treated to make fractures less visible or improve transparency.

Examples include:

• Oiling emeralds
• Filling fractures with resin or polymer
• Filling rubies with lead glass
• Impregnating porous gemstones
• Bleaching followed by polymer impregnation
• Coating a gemstone’s surface

A clarity enhancement does not necessarily make a gemstone unsuitable for jewelry, but the treatment must be disclosed. Treatments can affect value, stability, repair procedures and safe cleaning methods.

Glass-filled ruby, for example, is materially different from a traditionally heated ruby and usually occupies a much lower price category. An oiled emerald may require protection from heat, solvents, ultrasonic cleaning and steam.

Learn more in our Gemstone Treatments and Enhancements Guide.

How to Evaluate Gemstone Clarity

Begin by examining the gemstone face-up in normal lighting without magnification.

Ask the following questions:

1. Are any inclusions immediately visible?
2. Do they distract from the gemstone’s color?
3. Does the stone appear transparent, translucent or cloudy?
4. Are there large dark inclusions beneath the table?
5. Are any fractures open to the surface?
6. Are fractures located near corners, points or the girdle?
7. Could an inclusion affect setting or everyday wear?
8. Has the gemstone received a clarity treatment?
9. Is the observed clarity typical for this gemstone variety?
10. Does the gemstone remain beautiful when viewed normally?

Magnification can then be used to investigate features more closely. It should help explain what is already observed rather than encourage rejection of a beautiful stone because of harmless microscopic inclusions.

Clarity and Gemstone Value

Greater clarity does not automatically mean greater value. Color is generally the most important quality factor for colored gemstones.

A richly colored ruby with minor inclusions may be considerably more valuable than a clean ruby with weak or unattractive color. A slightly included emerald with vivid green color can be far more desirable than a cleaner but pale stone.

Clarity has the greatest negative effect when inclusions:

• Distract from color
• Reduce transparency
• Suppress brilliance
• Create an unattractive cloudy appearance
• Threaten durability
• Reveal an undesirable or unstable treatment

The ideal balance depends on the gemstone variety, rarity, intended use and price.

Laboratory Reports and Clarity

Major gemological laboratories generally identify colored gemstones rather than assigning them a universal quality or clarity grade.

A colored-stone report may state:

• The gemstone’s identity
• Whether it is natural or laboratory-grown
• Detectable treatments
• Weight and measurements
• Shape and cutting style
• Color description
• Geographic origin when requested and determinable

A report does not replace visual evaluation. Two stones with similar report descriptions can still differ significantly in transparency, beauty and value.

For important rubies, sapphires, emeralds, alexandrites and other valuable gemstones, an independent report can provide essential information about identity and treatments.

Choosing Clarity for Gemstone Jewelry

The best clarity is the level that preserves beauty and durability without requiring the buyer to pay for microscopic perfection that cannot be appreciated without magnification.

For an engagement ring, avoid gemstones with fractures that could worsen during frequent wear. For earrings and pendants, slightly more included stones may be acceptable because these pieces are generally exposed to less impact.

Judge the gemstone from a normal viewing distance first. Its color, brilliance and overall personality matter more than whether it looks flawless under a jeweler’s loupe.

Explore our complete guide to gemstones used in fine jewelry or continue with our guides to gemstone color and gemstone cut.