Diamond Inclusions Explained: The 2026 Guide to Feathers, Crystals, Clouds & Every Clarity Characteristic Inside Your Stone

When you hold a diamond grading report, the clarity grade printed on it—VS1, SI2, and so on—always tells a story written by inclusions. Far from being “flaws,” inclusions are proof that your diamond crystallized deep within the earth. They are a natural fingerprint unique to every single stone. This 2026 guide breaks down the most important inclusion types, what they look like, and how they shape a diamond’s beauty and value.

Inclusions vs. Blemishes

Clarity characteristics fall into two families. Inclusions are internal features, while blemishes are surface features. Under 10x magnification, the GIA and other labs assess both, then weigh five factors—type, size, number, location, and relief—to assign a grade on the 11-point scale from Flawless (FL) to I3. The key insight: clarity isn’t about whether inclusions exist, but about how noticeable they are.

The Most Common Inclusion Types

Feather

A feather is a tiny internal fracture. Depending on the viewing angle it can look transparent and nearly invisible, or catch the light with a whitish, feather-like appearance. Small feathers near the edges are usually harmless; large ones running through the center deserve a closer look for durability.

Crystal

A crystal is a mineral captured during growth. It can be colorless (a diamond within a diamond), black from carbon, red from garnet, or green from peridot. The larger and more colorful the crystal, the greater its impact on the grade.

Cloud & Pinpoint

Pinpoints are minute dots visible only under high magnification. When they cluster, they form a cloud—a hazy white area that, if extensive, can make a diamond look milky and dull its brilliance.

Needle, Twinning Wisp, Knot & Cavity

Needles are long, thin inclusions. Twinning wisps are ribbon-like features formed by crystal distortion, radiating from the center. A knot (a crystal reaching the polished surface) and a cavity (a surface opening left when a feather chips during polishing) are more visible and typically lower the grade.

The Five Factors Behind Every Clarity Grade

Two diamonds with the same “feather” can earn very different grades. Graders weigh (1) type, (2) size, (3) number, (4) location (center-table inclusions matter more than edge ones), and (5) relief (contrast against the surrounding diamond). The smart approach is to look past the letters and read the plotting diagram on the report, then choose an “eye-clean” stone whose inclusions are invisible to the naked eye.

ADAMAS: The Carefully Chosen Stone

At the luxury jewelry house ADAMAS, we select only the highest D-color diamonds with clarity that never interrupts their fire, set in enduring K18 gold. Understanding inclusions is your compass for choosing a piece you can truly treasure for a lifetime. Explore our collection of timeless brilliance at the ADAMAS official site, and discover the unchanging beauty your story deserves.