P grade refers to the clarity of a diamond, which is used to describe the severity of internal flaws or impurities in the diamond. In the international diamond 4C standard, diamond clarity levels are divided into five major levels and 10 sub levels, namely: LC，VVS1-2，VS1-2，SI1-2，P1-3。
Diamond clarity grading
Flawless Level (FL): When viewed under a 10x magnifying glass, diamonds have no inclusions or surface flaws
Under a 10x magnifying glass, there are no inclusions inside the diamond, and there are insignificant flaws on the surface that can be removed by polishing.
Under a 10x magnifying glass, there are extremely fine flaws inside the diamond, which are difficult for even professional appraisers to see.
Slight inclusions (VS) can be observed under a 10x magnifying glass, and diamond flaws are visible but very small.
Under a 10x magnifying glass, diamonds with micro inclusions (SI) exhibit clear and visible flaws.
The internal level (I) flaws are very obvious under a 10x magnifying glass and can also be seen with the naked eye, which affects the diamond's strength, transparency, and shine.