Treatments and disclosure

1. Positioning Statement

TGB operates on a disclosure-first model.
Every stone is presented with known treatments, observed indications, or a clear absence of evidence.

We do not assume.
We do not imply.
We state only what can be supported.

2. Disclosure Categories

Every stone listed under TGB will fall into one and only one of the following:

A. Untreated

  • No evidence of treatment observed under standard gemological testing
  • Does not guarantee absence of treatment
  • Indicates no detectable enhancement

B. No Indications Observed

  • No signs of treatment detected
  • Testing limitations acknowledged
  • Used where advanced testing has not been conducted

C. Heated

  • Evidence or trade-accepted likelihood of heat treatment
  • Applies across sapphire, ruby, tanzanite, etc.

D. Minor Treatment

  • Low-level clarity enhancement or stabilization
  • Does not materially alter structure or durability

E. Treated

  • Clear enhancement present
  • May include:
    • Filling
    • Dyeing
    • Coating
    • Irradiation
    • Diffusion
    • Oiling

3. Treatment Types

This is not how you list stones.
This is how you educate and anchor authority.

Heat Treatment

  • Common in: sapphire, ruby, tanzanite
  • Purpose: improve color and clarity
  • Stability: permanent

Oiling (Primarily Emerald)

  • Fills surface-reaching fractures
  • Improves apparent clarity
  • Requires maintenance over time

Resin / Polymer Filling

  • Used in emerald and lower-grade corundum
  • More stable than oil, less accepted in high-end trade

Irradiation

  • Used in topaz, diamond
  • Alters color through radiation exposure
  • Generally stable but must be disclosed

Diffusion Treatment

  • Surface-level or lattice penetration (e.g., sapphire)
  • Can significantly affect value
  • Often difficult to detect without advanced labs

Coating

  • Applied to surface to alter color or effect
  • Least stable form of enhancement

4. Disclosure Language

Every listing follows this structure:

  • Treatment: [Category]
  • Notes: [Specific treatment if known]

Example

Treatment: Heated
Notes: Standard heat treatment, no residues observed

5. Limitations Statement

Gemological testing is non-destructive and subject to limitations.
The absence of detected treatment does not guarantee that a stone is untreated.

Where advanced laboratory testing has not been conducted, disclosures are based on standard trade practices and observable evidence.

6. TGB Position

TGB does not price stones as “untreated” unless:

  • Evidence supports it, or
  • It has been confirmed by a recognized gemological laboratory

All other stones are priced according to market reality, not assumption.