The SSEF IIa Diamond Spotter™ and its Illuminator:
De-colorization (!) of (brown) diamonds was proved to be feasible
for high pressure/high temperature treated IIa diamonds (GE POL, Bellataire,
see above). The first step for an identification of such stones is
the recognition of their IIa behaviour, i.e. transmission of short
wave ultraviolet light. All type IIa (and rare type IaB) transmit
short-wave ultraviolet (SWUV) light.. Most diamonds are type Ia and
do not transmit SWUV.
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| The SSEF IIa Diamond Illuminator™ is
an ideal light source for the detection of type IIa diamonds with
the SSEF IIa Diamond Spotter™. |
Especially for the diamond trade the SSEF has developed
the SSEF IIa Diamond Spotter™, a small instrument that
works in connection with a short-wave ultraviolet light source. Ideally,
the Diamond Spotter is combined with the new SSEF IIa Diamond illuminator™,
a small portable 110/220V SWUV light source, which produces a monochromatic
radiation of 254 nm.
The screen of the SSEF IIa Diamond Spotter™ is made of a substance
that fluoresces when exposed to a SWUV light source. By placing a
diamond into the Spotter and switching on the SWUV light source, the
diamond will react by transmitting or absorbing the SWUV light, thus
fluorescence or no fluorescence on the screen of the Spotter. In the
case of a green fluorescent light spot on the screen, the diamond
transmits SWUV and is thus of type IIa (or rare type IaB) and may
have been "decolourised" by HPHT treatment. If no
reaction, the colourless diamond is not a IIa diamond, thus not
HPHT treated.
When a colourless IIa diamond is identified by its transmission of
SWUV, the stone should be further analysed in a specialised gem laboratory
(e.g., SSEF) where the HPHT treatment can be identified by Raman luminescence
spectrometry.
The SSEF IIa Diamond Illuminator™ is sold
with adapter and voltage converter by SSEF for US$ 500 or US$ 650
together with an SSEF IIa Diamond Spotter™ (plus shipment).
The Spotter alone is US$ 150 (plus shipment). For further information,
e-mail gemlab@ssef.ch
