AIGS Laboratory Disclosure Comments for Color Gemstones.

Effect of Heat Treatment

No.Residue found

Residue in Fissures

Residue in Cavities

Amount of Residue

none

minor

moderate

significant

minor

moderate

significant

AIGS  Grading Code

HT

HT(minor)

HT(moderate)

HT(significant)

HT(1)

HT(2)

HT(3)

Example: HT (minor2) means minor amount of residues in fissures and moderate amount of residues in cavities.

HT : Indications of heating.

HT (lead) : lead-rich vitreous residue in fissures and/or cavities.

HT (bismuth) : bismuth-rich vitreous residue in fissures and/or cavities.

HT (lead+bismuth): lead and bismuth-rich vitreous reside infissures and/or cavities.

HT (elements) :
This stone shows indications of heating. the color is modified/altered by the introduction of one or  more chemical elements from an external source.The extent of the color modification can be shallow or deep.In the case of light elements (e.g. beryllium), the color is stable and it is normally present in the entire stone. For some other elements (e.g. irom/titanium), the artificially created color generally lies just at and below the surface in a thin layer. This color is also stable, but may be removed by (re) cutting or (re)polishing.

Remark : The mention “not LIBS tested” on a report means that the stone wasn’t tested for treatment with light elements.

Definition of Jadeite comment


Type A : No indication of enhancement.


Type B : Indication of bleaching and polymer impregnation.


Type C : Indication of dyeing.


Note: New codes are effective starting from 1 Nov 2013.
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