Diamond Grading and Identification Course


We at INDRAPRASTHA GEM & JEWELLRY INSTITUTE through DGIC cover the complete knowledge about the identification and grading of diamond. This program covers complete theoretical and practical training on all the aspects of diamond grading & identification techniques. Special emphasis will be given on “ QUICK SIGHT SYSTEM” by teaching the main 4C’S of Diamonds i.e CUT, COLOR, CLARITY & CARAT, which is very essential in Grading and price evaluation . Due to specialize nature of the Diamond Grading course and need for accurate and reliable study material, IGL provide course and final examination. However additional reading around the subject is always recommended. We also help you to identify/ separate diamond from its various simulants.

  • Paper DG1- Theory examination -3 hours
  • Paper DG2- Practical examination – 3 hours

Diamond grading syllabus

Due to the specialized of the Diamond grading course and the need of accurate and reliable study materials, IGL provides course notes to guide and assist students through the course and final examinations, however, additional reading around the subject is always recommended. For future information about the course materials available please contact IGL.


  • DG1- History of Diamond

The brief history of discovery and mining developments; diamond localities and their historical significance; mine output and gem output in relative terms.

  • DG2- Diamond Origin and Occurrence

Geological significance of diamond origin, discovery and occurrence. The dynamic geological environment of diamond and its conditions of growth; evidence for origins. Geographical distribution and mine localities in terms of geological occurrence: primary and secondary occurrence

  • DG3 The nature of diamond

The structure of diamond; chemical bonding and crystalline patterns of carbon atoms; diamond crystal from and habit, growth and etch markings, cleavage, growth planes and ‘ grain’. Classification of diamond in the cubic crystal system.

  • DG4 the Properties of Diamond

The major physical properties of diamond the relevant description of the gemological properties 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.

  • DG5 Color in Diamond
  • Description of the importance of crystalline imperfection and diamond type; the mechanism and major influence of imperfections on color and electrical properties; absorption characteristics. Ultraviolet radiation; fluorescence and phosphorescence.

  • DG6 Synthetic gem – quality diamond

Methods conditions and example of modern synthesis of gem – quality diamond

  • DG7 Diamond treatments

Example and mechanisms of various types of production and alteration including irradiation and heat treatment, high temperature high – pressure treatment. Surface color alteration including painting and foiling. Clarity treatment; laser – drilling. KM laser treatment and glass filling of surface – reaching cavities.

  • DG8 Testing diamonds

The main laboratory testing tools used to test diamond, Including the DTC screening tools.

  • DG9 Mining and recovery

The main methods of modern mining; open – pit and underground mining . Diamond – pipe and alluvial diamond mining including marine mining. Stages of recovery: treatment: concentration and separation.

  • DG10 Diamond Manufacturer

Methods of manufacturer. The round brilliant cut: designing the rough, dividing, shaping: faceting and polishing. Sawing planes and polishing grain. Use of lasers and automation.

  • DG11 History of Diamond Cuts

A brief history of the development of cutting. The cuts New cuts, Quality of cut and ideal proportions for diamond. Proportion measurement.

  • DG12 The diamond pipeline

Sizing and shapes of rough. Sorting for quality and color. The rough diamond market, DTC, conflict diamonds and the Kimberley Process. The polished diamond market. Cutting centers and diamond bourses.

  • DG13 Diamond grading, valuation and diamond in jewelry

The 4C's color; clarity; cut and carat weight; the grading system and the principles of grading reports. The basis of appraisal and valuation. Common diamond settings.

  • Diamond Simulants

Diamond simulants,natural or artificial. Assembled (composite) stones. Identification of diamond; distinction of diamond from its simulants by means of external and internal characteristics, particularly with the use of 10x lens; by the use of instruments, including the use of diamond testers, specific gravity, fluorescence, X- ray.

  • Practical syllabus

PART A - Contains thirteen loose polished stones; each diamond will have been pre – graded in IGL according to GIA and CIBJO system. One stone will be viewed at a time. Part A requires diamond identification, color grading clarity grading description of summitry, proportions and girdle details, detection of treatments and detection ( but not identification ) of simulants.

One or more of the stones in Part A may be a treated diamond, or an assembled stone. Color ad clarity grading of fracture – filled stones is not required. Both color and clarity grading of laser – drilled stones is required

PART B - Contains 6 diamond simulants. Mix up with some diamonds

If a candidate state that a diamond is a diamond stimulant, or that a diamond stimulant is a diamond, this is counted as a wrong identification.

Students are required to carry out the following

  • Identification of diamond and distinction of diamond from its simulants. To identify diamond using 10X lens only. Simple tests to distinguish diamond from simulants. Identification of the simulants species is not required.
  • Detection of diamond treatments; the detection of laser drill – holes made to improve the appearance of diamond inclusions. The detection of artificially – filled fractures reaching the surface (fracture- filled diamonds)
  • Cut grading visual estimation of table symmetry and approximate table diameter percentage using the 10X lens and the ‘bowing ‘ method; crown angle by ‘ third of right angle ‘ method; pavilion depth by ‘ ratio ‘ method; estimation of ‘ fish – eye’ and ‘ lumpy extremes ‘. Girdle width and condition.
  • Color grading; use of a folded white card grading lamp, with or without color comparison (master) stone, to assess color grade using the CIBJO/GIA system color grades.

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