US 12,292,385 B2
Gemstone colour grading process and grading system
Wing Yan Lee, Hong Kong (CN); Juan Cheng, Hong Kong (CN); Chun Yan Dominique Lau, Hong Kong (CN); Wing Chi Tang, Hong Kong (CN); Ka Wing Cheng, Hong Kong (CN); Ching Tom Kong, Hong Kong (CN); and Koon Chung Hui, Hong Kong (CN)
Assigned to GOLDWAY TECHNOLOGY LIMITED, Hong Kong (CN)
Appl. No. 17/312,240
Filed by GOLDWAY TECHNOLOGY LIMITED, Hong Kong (CN)
PCT Filed Dec. 10, 2019, PCT No. PCT/CN2019/124269
§ 371(c)(1), (2) Date Jun. 9, 2021,
PCT Pub. No. WO2020/119673, PCT Pub. Date Jun. 18, 2020.
Claims priority of application No. 18115828.6 (HK), filed on Dec. 10, 2018.
Prior Publication US 2022/0026371 A1, Jan. 27, 2022
Int. Cl. G01N 21/87 (2006.01); G01J 3/42 (2006.01); G01N 21/31 (2006.01); G01N 24/10 (2006.01); G01N 33/00 (2006.01); G01R 33/60 (2006.01)
CPC G01N 21/87 (2013.01) [G01J 3/42 (2013.01); G01N 21/3103 (2013.01); G01N 24/10 (2013.01); G01N 33/389 (2024.05); G01R 33/60 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A process of assigning a colour grade to a diamond, said process including the steps of:
(i) determining the N3 and C-center content of a diamond;
(ii) comparing the N3 and C-center content of said diamond with a previously acquired data set from a plurality of diamonds each having a colour grading previously assigned thereto, and
(iii) assigning a colour grade to the diamond upon a correlation of the N3 and C-center content of said diamond with a grade of said previously acquired data set;
wherein said previously acquired data set comprises a correlation between N3 and C center content and optical absorbance in the visible light spectrum for each diamond of said plurality of diamonds.