A cloud is many tightly grouped pinpoints that are too small to see one by one but together look hazy.
In more detail
A cloud is an inclusion. A large cloud can lower the transparency of a stone.
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
- Pinpoint: A pinpoint is a very small crystal inside a diamond that looks like a tiny dot at 10x.
- Twinning wisp: 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.
- Included (I1, I2, I3): I1, I2 and I3 are the lowest clarity grades. Their inclusions are obvious at 10x and can affect transparency and brilliance.
- Inclusion: An inclusion is a clarity characteristic inside a diamond, or one that reaches the surface from inside.