A laboratory-grown diamond is a diamond that people grow with machines, by HPHT or CVD. It has essentially the same composition, crystal structure and properties as a natural diamond.
In more detail
It is diamond, not a simulant. In our simulator it renders identically to a natural diamond, pixel for pixel; only a lab can tell them apart. Do not confuse "lab-grown diamond" with "lab-grown moissanite": both are made in a lab, but only one is diamond.
On a grading report
Since 1 October 2025, GIA rates a colorless to near-colorless lab-grown diamond Premium or Standard, with no D-to-Z or clarity grade. It inscribes "Laboratory-Grown" and the assessment number. IGI inscribes "LG" before the report number and can note the growth method in Comments.
Related terms
- Natural diamond: A natural diamond is a diamond that formed in the earth, about 160 km deep, under enormous heat and pressure. An eruption carried it to the surface.
- HPHT: HPHT stands for high pressure, high temperature. The same conditions can grow a diamond in a laboratory or treat a natural one to change its color.
- CVD: CVD, chemical vapor deposition, is one of the two usual methods for growing diamond in a laboratory. The other is HPHT.
- Laboratory-Grown Diamond Report: The Laboratory-Grown Diamond Report was GIA's digital-only report for laboratory-grown diamonds, from October 2020 to September 2025. It gave color and clarity grades and stated the growth method, CVD or HPHT.
- Simulant: A simulant is a material that looks like a gem but has a different chemistry, structure and properties. Cubic zirconia, moissanite and glass are diamond simulants.