Diamond Grading & Sorting

Paper Code: 
JWT 504(B)
Credits: 
8
Contact Hours: 
120.00
Max. Marks: 
100.00
Objective: 

This course will enable the students to-

  • Grade diamonds consistently and accurately using a modern gem microscope and loupe.
  • Recognize the most common diamond features.
  • Study of 4 ‘C’s of diamonds, Use of various Gemology instruments.

 

20.00
Unit I: 
Uses of various instruments:

                                                    

Refract meter, Polariscope, Microscope, Spectroscope, Ultraviolet lamp , Hardness pencil ,  Diamond probe, Chelsa  filter, 10x lens. MM Watch, optimizer, sieve  etc

 

20.00
Unit II: 
Properties of Diamond

 

The physical properties of diamond and their practical exploitation. Dispersion and ‘fire; total internal reflection; reflectivity and luster;brilliance.

Directional optical properties; durability, specific gravity (SG), electrical properties; thermal properties; wettability.

Non – optical directional properties; ‘grain’ cleavage, differential hardness and crystal from in relation to the crystal structure of diamond; their significance in identification and manufacture.

 

20.00
Unit III: 
4 C’s of Diamonds and grading

 

  • Cut Grading of diamonds : Ideal proportions for diamond brilliant cut (GIA)
  • Table angle and depth
  • Crown angle and height
  • Girdle thickness and angle
  • Pavilion angle and depth
  • Clarity Grading
  • Types of inclusions in diamond
  • Types of Blemisses
  • Percentages of inclusions and blemisses
  • Clarity chart (GIA)
  • Color Grading
  • Using color master
  • Color scale of diamond (GIA)
  • Carat Weight and size
  • Unit weight of Cents(Ct) carat weight
  • Use of Millimeter Gauge

 

30.00
Unit IV: 
Color in Diamond
  • Color Grading
  • Grade diamonds in the D-to-Z color range
  • Detect laboratory-grown diamonds, treatments, and stimulants

 

30.00
Unit V: 
Clarity grading
  • Practical clarity grading
  • Internal & External features which effects clarity grading
  • Grading and sorting of diamonds from small size to solitaire
  • Examine various diamond samples with 10x lens and under microscope. Practice of grading them according to grading charts.

 

 

Essential Readings: 

Books Recommended:

  • Spear, K. E., & Dismukes, J. P. (Eds.). (1994). Synthetic diamond: emerging CVD science and technology (Vol. 25).
  • John Wiley & Sons. Neves, A. J., & Nazaré, M. H. (Eds.). (2001). Properties, growth and applications of diamond IET.
  • Smith, G. (2003). The allure, magic and mystery-A brief history of diamonds. Journal of the Southern African Institute of Mining and Metallurgy, 103(9), 529-534.
  • Kendall, L. P. (2001). Diamonds: Famous and Fatal: the History, Mystery, and Lore of the World's Most Precious Gem. Barricade Books.
  • Pagel-Theisen, V. (2001). Diamond grading ABC: The manual. Rubin & Son.

 

 

 

Academic Year: 
2019-20
  • Printer-friendly version
  • PDF version