Equipment

Colorimetric stone is the lower limit colorimetric stone, the range is E-L;
 

Colorimetric stone colorless - yellow color series;
 

The purity of colorimetric stone is vvs₁-vs₂.
 

The colorimetric stone is a standard round diamond cutter.
 

The weight of colorimetric stone was 0.30ct-0.35ct.
 

Each grain of colorimetric stone has been strictly calibrated by professional institutions, that is, marked with position coordinates;
 

The colorimetric stone has no fluorescence or weak fluorescence
 

Other: diamond fluorescence intensity specimens: strong, medium, weak, no four
 

Usage:
 

If a diamond to be graded has the same color as a grain in the colorimetric stone, the color level of the colorimetric stone is the color level of the diamond to be graded.
 

When the color of the diamond to be graded is between two adjacent colorimetric stones, the lower grade indicates the color level of the diamond to be graded.
 

Until the color of the graded diamond is higher than the highest grade of the colorimetric stone, the color grade of the diamond is still indicated by the highest grade.
 

When the grading diamond color is lower than "N" colorimetric stone, it is indicated by "