Gemstone Treatments¶
Heat treatment, filling, diffusion, coating, and detection methods.
Interactive Version
For detailed data tables and interactive content, visit gemmology.dev/learn/treatments.
Disclosure Requirement
All gemstone treatments must be disclosed at the point of sale. Undisclosed treatments are considered fraudulent.
Heat Treatment¶
The most common treatment, permanently alters colour and clarity.
| Gemstone | Effect | Temperature |
|---|---|---|
| Blue sapphire | Improves colour, dissolves silk | 1400-1800°C |
| Ruby | Improves colour | 1200-1800°C |
| Tanzanite | Brown → blue-violet | 450-650°C |
| Aquamarine | Removes green tint | 400-450°C |
Detection Signs¶
- Dissolved or partially dissolved silk
- Stress fractures around inclusions
- Altered absorption spectrum
Fracture Filling¶
| Filler | Gemstone | Stability |
|---|---|---|
| Cedar oil | Emerald | Can dry out |
| Resin | Emerald | More stable |
| Lead glass | Ruby | Fragile - damaged by heat, acids |
Lead Glass-Filled Rubies
These stones can contain more glass than ruby and are extremely fragile. Damaged by heat, ultrasonic cleaning, and even lemon juice.
Diffusion Treatment¶
| Type | Element | Result |
|---|---|---|
| Surface | Titanium | Blue sapphire (shallow) |
| Lattice | Beryllium | Orange/pink sapphire (deep) |
Treatment Acceptance¶
| Widely Accepted | With Disclosure | Controversial |
|---|---|---|
| Heat (corundum) | Resin filling | Lead glass filling |
| Oil (emerald) | Be diffusion | Surface diffusion |
| Waxing | Irradiation | Coatings |
Data source: learn/treatments.yaml