| 摘要 |
PROBLEM TO BE SOLVED: To synthetically and fairly evaluate objectivity of value in commodity transaction by judging color grade and clarity grade of a diamond by visual observation and simultaneously measuring brightness to light source which is incident on the diamond from table face side of the diamond. SOLUTION: Measurement of brightness by optical equipment in addition to measurements of dimensions, finishing, color grade and clarity grade of diamond is made to be comparable with evaluation of color grade and clarity grade by artificial, judgment and thereby, brightness of diamond itself is objectively corrected to enable evaluation of fair and synthetical grade. When certification of authenticity of diamond is prepared, after measurement of visual observation, diamond is set toward the upper direction of a table on a base of black and light having a constant light intensity is made to be incident on the diamond from a ring-like fluorescent lamp 13 of upper end of black cylindrical jig 11 and reflected light is received to optical equipment 14 such as a luminance meter above the opening and brightness (cd/m<2> ) is displayed on a display 15 and determined. |
