---
title: "Needle: meaning in gemology"
description: "A needle is a thin, elongated crystal inclusion that looks like a tiny rod at 10x."
url: https://digitalgemology.com/learn/glossary/needle
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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[Glossary](https://digitalgemology.com/learn/glossary) · Clarity characteristics

# Needle

Also called needles, rutile needle, needle inclusion

A needle is a thin, elongated crystal inclusion that looks like a tiny rod at 10x.

## In more detail

In corundum, needles are often rutile; crossing groups of them are called silk. In moissanite, GIA found thin white needles, roughly parallel, running down from the table along the optic axis. That pattern is a hint toward moissanite, not proof.

## On a grading report

Drawn in red on the clarity plot of a full GIA report and named in the key to symbols. A Dossier has no plot but can name it in its list of up to four.

## Related terms

- [Crystal](https://digitalgemology.com/learn/glossary/crystal-inclusion): A crystal is a mineral crystal contained in a diamond.
- [Silk](https://digitalgemology.com/learn/glossary/silk): Silk is a mass of fine, crossing needle inclusions, usually rutile, in ruby and sapphire.
- [Moissanite](https://digitalgemology.com/learn/glossary/moissanite): Moissanite is silicon carbide, one silicon atom for every carbon atom, in a hexagonal crystal. It is a diamond simulant, and every moissanite in jewelry is laboratory-grown.
- [Inclusion](https://digitalgemology.com/learn/glossary/inclusion): An inclusion is a clarity characteristic inside a diamond, or one that reaches the surface from inside.

## Learn more

- [The loupe test: doubled facet edges in moissanite](https://digitalgemology.com/learn/diamond-vs-moissanite/moissanite-doubled-facets-loupe-test)
- [Emerald Square Cut Ruby: a step-cut square that holds its light when tilted](https://digitalgemology.com/gemstones/ruby/emerald-square)

[All 328 terms](https://digitalgemology.com/learn/glossary)