What is a feather inclusion in a diamond?
By Jared James · Last updated 21 May 2026
Definition
In gemmology, a feather is a small fracture or crack inside a diamond or other gemstone, named for its wispy, feathery appearance under magnification. Feathers can be white and reflective or nearly transparent depending on how the light hits them. A small feather that does not reach the surface is generally of little concern, but a large feather extending toward a facet edge can pose a risk of chipping over time and deserves careful assessment before buying.
Frequently asked questions
- Is a feather inclusion bad in a diamond?
- It depends on the size and position. A tiny feather deep inside the stone with no path to the surface is a minor clarity characteristic and is perfectly normal. A large feather near the surface or running across a facet edge needs more careful consideration, as it can be vulnerable to knocks.
- Can a feather inclusion cause a diamond to break?
- A small feather is unlikely to cause any problems in normal wear. A significant feather, especially one reaching the surface or the girdle, could propagate if the stone is knocked hard at that point, so it is worth asking a jeweller to assess the risk before buying.
- How do feathers show up on a diamond grading report?
- GIA and other labs will note feathers on the clarity plot in a grading report, usually shown as red lines indicating internal characteristics. The clarity grade itself reflects how much they affect the stone overall when viewed under 10x magnification.
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