Inclusion names describe observed clarity characteristics, not a verdict on the stone. Their grade effect and possible visibility depend on size, number, position, nature, and color or relief, while durability questions need item-specific examination.

A careful glossary of common diamond inclusion names that connects crystals, pinpoints, clouds, feathers, needles, knots, cavities, and wisps to report plots without assigning risk from a label alone.

What this guide covers

Learn what the common characteristic names describe.
Locate plotted features on the applicable report without treating the plot as life-size.
Separate grade effect, unaided-eye visibility, condition, and durability review.

Group inclusion terms by what they describe

Contained crystals

Crystal, pinpoint, and needle describe solid features at different apparent scales or shapes under magnification.

Grouped features

A cloud is a concentration of pinpoints that may create a hazy area, while a twinning wisp combines growth-related characteristics.

Break-related terms

Feather is a trade term for a break; a cavity is an angular surface opening, and each needs its own location and extent reviewed.

Surface-reaching crystal

A knot is a diamond crystal that reaches the polished surface; the name does not by itself state visibility or consequence.

Read a clarity plot in context

1 — Match symbol to legend
Use the actual report's key and comments rather than assuming every laboratory plots or names characteristics the same way.
2 — Find position and orientation
Relate the plotted location to the face-up and pavilion diagrams while remembering that symbols are schematic.
3 — Ask the right follow-up
Review visibility, transparency, surface reach, current condition, setting relationship, and any treatment as separate questions.

An inclusion name is not a damage rating

Scope boundary · evidence version 2026-07-19
This glossary cannot grade, identify, or evaluate one diamond. It must not turn feather, cloud, crystal, knot, cavity, or another term into a blanket beauty, value, visibility, or durability conclusion. A qualified examination and the complete report set the item-specific boundary.

Diamond inclusion questions

Is every feather dangerous?

No blanket conclusion follows from the name. Size, location, surface reach, orientation, stone condition, and setting work need review.

Is a cloud one large inclusion?

It is a group of pinpoints whose combined appearance can vary; the exact stone determines its effect.

Does the plot show everything I can see?

No. It is a symbolic map of selected characteristics, not a life-size photograph or complete condition record.

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