Diamond Inclusions to Avoid: A Complete Buyer’s Guide

Diamonds are known for their brilliance, durability, and timeless appeal. But no diamond is completely perfect. Almost every stone has natural imperfections known as inclusions—tiny internal features formed during the diamond’s growth process.

Some inclusions are harmless and nearly invisible, while others can seriously affect beauty, durability, and value. If you’re in the market for a diamond, it’s essential to know which inclusions are acceptable and which diamond inclusions to avoid.

This guide explores what inclusions are, how they affect quality, and which types you should steer clear of when shopping for a diamond.

What Are Diamond Inclusions?

Inclusions are natural internal features that form as carbon crystallizes under extreme high pressure and high temperature conditions deep within the earth. They are essentially “birthmarks” that make each diamond unique.

The Gemological Institute of America (GIA) defines diamond clarity as one of the famous 4Cs (alongside cut, color, and carat). Clarity measures the presence, size, number, and position of inclusions. Diamonds are graded on a scale from Flawless (no inclusions visible under 10x magnification) to Included (inclusions visible to the naked eye).

Within this system, stones with higher clarity grades command greater value, while those with more imperfections fall into the slightly included or included categories. Some inclusion types—such as small crystal inclusions or faint internal graining—may be invisible to the naked eye, making them less of a concern. Others, such as dark inclusions, black carbon spots, or large cloud inclusions across the surface of a diamond, can dramatically impact beauty and value.

Certain inclusions even affect durability. Features that reach the surface of the diamond, like feathers or cavities, can weaken structure and make the stone more vulnerable during wear or the cutting process. Treatments such as laser drilled holes are sometimes used to reduce visibility of black spots, but these may also lower value. More complex inclusions like twinning wisps or heavy clouding can dull sparkle, leaving the diamond looking less brilliant.

When evaluating clarity diamond quality, the goal is to avoid inclusions that stand out on the surface of the diamond or interfere with light performance. While every stone has unique characteristics, knowing which inclusions to avoid will help you choose a diamond that looks beautiful and remains durable for generations.

Why Inclusions Matter

Inclusions impact a diamond in three major ways:

1. Appearance – Large or poorly placed inclusions may reduce sparkle or be visible to the naked eye.
2. Durability – Some inclusions weaken the stone’s structure, increasing the risk of chipping or cracking.
3. Value – Diamonds with noticeable inclusions are less rare and therefore less valuable.

When shopping, the goal is to find a stone that appears clean to the naked eye (called “eye-clean”) while avoiding inclusions that compromise durability.

Types of Diamond Inclusions

Not all inclusions are created equal. Below are the most common types you’ll encounter, along with advice on which diamond inclusions to avoid.

1. Crystals or Mineral Inclusions

These are small crystals or minerals trapped inside the diamond during formation. They can appear white, black, or even colored.

• Harmless: Tiny white crystals often go unnoticed.
• Avoid: Large black crystals near the center of the table (the diamond’s top surface) because they are easily visible and distracting.

2. Pinpoints

Tiny dots within the diamond, often appearing as specks under magnification.

• Harmless: Single pinpoints are usually invisible to the naked eye.
• Avoid: Groups of pinpoints that create a hazy effect, known as “clouds.” These can reduce brilliance.

3. Clouds

Formed when multiple pinpoints cluster together. They may make the diamond look milky or dull.

• Avoid: Large clouds, especially if they cover the table, because they can dramatically reduce sparkle.

4. Feathers

Feathers are small internal cracks that resemble white feather-like patterns.

• Harmless: Tiny feathers on the edges that don’t affect durability.
• Avoid: Large feathers near the girdle (outer edge) or extending to the surface, since they can weaken the diamond and increase the risk of chipping.

5. Cavities

Hollow openings on the diamond’s surface. These occur when a crystal falls out during polishing.

• Avoid: Cavities on the table or crown because they’re visible and can collect dirt.

6. Chips

Small breaks or notches usually found near the girdle. Chips can occur during wear, setting, or handling.

• Avoid: Any diamond with visible chips, since they compromise beauty and durability.

7. Knots

A crystal that reaches the diamond’s surface, usually noticeable under magnification.

• Avoid: Prominent knots, as they can affect polish and make the surface uneven.

8. Internal Graining

Lines or streaks caused by irregular crystal growth. They may appear as faint lines, angles, or haze.

• Harmless: Light internal graining visible only under magnification.
• Avoid: Heavy graining that makes the stone look cloudy.

9. Needles

Long, thin crystal inclusions resembling tiny needles.

• Harmless: Isolated needles off to the side.
• Avoid: Clusters of needles visible to the naked eye.

10. Twinning Wisps

These appear as streaks or swirls formed during crystal growth. They can include clouds, pinpoints, or crystals.

• Harmless: Small wisps in less noticeable areas.
• Avoid: Large, dense wisps that give the diamond a hazy look.

Inclusions to Avoid in Specific Locations

Even small inclusions can be problematic depending on where they’re located:

• Under the Table: Inclusions directly beneath the diamond’s top surface are most visible and should generally be avoided.
• Near the Girdle: Feathers or chips in this area increase the risk of chipping.
• In the Pavilion: Some inclusions here may reflect multiple times, making them look larger.

Inclusions hidden under prongs or along the edges are less noticeable and may be acceptable if they don’t compromise durability.

How Clarity Grades Relate to Inclusions

The GIA clarity scale includes:

• FL (Flawless) – No inclusions visible at 10x magnification.
• IF (Internally Flawless) – No inclusions inside, only surface blemishes.
• VVS1–VVS2 (Very Very Slightly Included) – Inclusions are extremely difficult to see even under magnification.
• VS1–VS2 (Very Slightly Included) – Minor inclusions that are hard to spot with the naked eye.
• SI1–SI2 (Slightly Included) – Inclusions may be visible to the naked eye in SI2, but SI1 stones are often “eye-clean.”
• I1–I3 (Included) – Inclusions are obvious and may affect durability.

For most buyers, VS2 or SI1 clarity offers the best balance of affordability and appearance. The key is to avoid inclusions that compromise durability or sparkle.

Tips for Avoiding Problematic Inclusions

1. Inspect the Stone – Always view diamonds in person or request high-resolution images and videos if buying online.
2. Check with 10x Magnification – Use a jeweler’s loupe to spot inclusions not visible to the naked eye.
3. Ask About Placement – Inclusions near edges may be less concerning if hidden by a setting.
4. Work with Certified Stones – Always choose diamonds with grading reports from GIA or AGS for transparency.
5. Trust Your Eye – If an inclusion bothers you, even at a lower price, it may not be the right stone.

The Role of Certification

Certification protects buyers by providing a third-party evaluation of inclusions. A GIA certificate includes a clarity grade and a detailed plot showing where inclusions are located. This helps you understand what you’re buying and avoid surprises later.

Without certification, it’s difficult to verify whether inclusions are minor or serious.

Do Inclusions Always Lower Value?

Not necessarily. Some inclusions are so small they don’t affect appearance or durability. In these cases, they may have little to no impact on value.

However, large, dark, or poorly placed inclusions will reduce a diamond’s price. Savvy buyers can use this to their advantage—choosing diamonds with inclusions hidden under prongs or invisible to the naked eye to maximize value without overpaying for “flawless” grades.

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Inclusions are a natural part of almost every diamond. They tell the story of the stone’s formation deep within the earth. But when shopping for a diamond, it’s important to know which inclusions are harmless and which diamond inclusions to avoid.

Steer clear of large feathers, black crystals under the table, cavities, chips, and heavy clouds that dull brilliance or weaken structure. Instead, look for stones that appear clean to the naked eye, even if they contain minor inclusions only visible under magnification.

By understanding inclusions, working with trusted jewelers, and insisting on certification, you can find a diamond that sparkles beautifully, stands the test of time, and delivers the best balance of beauty, durability, and value.

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Book a Diamond Appointment  with our experts and let us help you find the perfect natural diamond for your engagement.