There is a growing need in the diamond industry for a widely accepted and reliable cut grading system. Developing such a system, acceptable and beneficial to all parties, is a complex task involving the optics of the stone as well as human taste and physiology. The development of new technology, devices and approaches will require communication and implementation in all industry sectors.

This presentation will be devoted to explanation of methodology of diamond cut grading. In this methodology we avoid to grade cut on the base of proportions and similar parameters. We are putting various optical responses of diamond on the base of cut grading. This approach will allow developing of unified cut grading system that will be also applicable on fancy shapes and other (non diamond) gem materials. This system allows to grade cut for various segments of market and consumer groups. We will also discuss why a 3d diamond model is more perspective for cut grading than a parametrical diamond model, and why it is impossible to develop an universal cut grading system on the base of set of diamond parameters.

The main topics of the presentation:

Diamond Cut Study: goals, tasks, problems.

History of diamond cut study: articles, approaches, instruments.

Methodology of a diamond cut grading system: development and application.

• Stage 1. Understanding of basic phenomena. Work with parametrical cut.
• Stage 2. Verification. Work with real diamonds.
• Stage 3. Cut grading system and cut grades development.
• Stage 4. Practical applications of cut grading.

Highlights of MSU diamond cut study

Factors that determine the cut quality

Psychophysiology of human vision.

How to grade diamond symmetry?

OctoNus tools to grade cut.

What is a good diamond?

What is a bad diamond?

Conclusion.