Various enhancement treatments and stone-fabrications in use today:

Fabrications, reproductions and outright frauds:

1. Foil-backed mountings

2. Imitation or simulated gems

3. Doublets or composite stones

Enhancements:

1. Synthetic lab-produced stones [made up of the same basic chemical composition as a natural gemstone].

2. Dyeing techniques

3. Painting effects

4. Fracture-filling techniques [epoxy resins, oils, waxes and glue]

5. Heat-treatment

6. Radiation treatment

7. Diffusion treatment [also called ‘surface diffusion']

8. HPHT treatment [High pressure, high heat treatment]

9. Bleaching

10. Impregnation and coating with plastic or wax

11. Laser drilling