A twinning wisp is a series of pinpoints, clouds or crystals that forms in a diamond's growth plane. It comes with crystal distortion and twinning planes.
In more detail
It forms along a twinning plane, where the crystal structure changes direction. GIA lists it among the inclusions.
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
- Cloud: A cloud is many tightly grouped pinpoints that are too small to see one by one but together look hazy.
- Pinpoint: A pinpoint is a very small crystal inside a diamond that looks like a tiny dot at 10x.
- Internal graining: Internal graining is lines, angles or curves inside a diamond caused by irregular crystal growth. At 10x they can look whitish, colored or reflective, or lower the transparency.
- Inclusion: An inclusion is a clarity characteristic inside a diamond, or one that reaches the surface from inside.