Four tests on one rough stone, and only the last one settled it

§1A stone that looked like ordinary rough.

The Israeli Diamond Institute's technology department reports that a rough stone submitted to it on Tuesday 18 August, which passed an initial visual screening as ordinary natural rough, was classified as laboratory-grown by infrared spectroscopy. The account appears on the institute's own site, dated 25 August and bylined to Sergey Lazon, a certified gemologist there. This paper carries it as a single-source item. The testing laboratory is describing its own test, no independent outlet has reported it, and no submitting party, dealer or company is named.

§2Four steps, and only the fourth settled it.

The sequence matters more than the result. On first examination the stone's recorded data matched expected parameters and it looked externally like natural rough. Under the microscope it showed small clouds and inclusions of the kind natural rough carries, but also minor defects the institute describes as atypical of natural diamond and consistent with CVD growth. A dedicated CVD screening device then returned a preliminary indication of laboratory origin, which the institute qualifies itself, noting that such devices can give ambiguous readings where inclusions are weak. Fourier transform infrared spectroscopy gave what the institute calls an unambiguous result and classified the stone as Type IIa. Four steps, and the institute's own account treats only the fourth as settling anything.

§3Rough is where the defences were never built.

Rough is where this is hard, and cut goods are where the trade's defences were built. A polished stone can be screened at speed against a large body of known optical behaviour, and the major laboratories have spent a decade automating that. A rough stone has no facets to read through, its surface is its skin, and the visual cues a sorter relies on, the clouds and included crystals named in this account, are the cues this stone presented correctly. Type IIa is the crux. It is the nitrogen-poor category most laboratory-grown diamond falls into, and the institute's position is that natural origin is difficult to argue for a Type IIa stone with this rough's structure and shape. Type IIa natural rough exists and is prized, which is exactly why a false negative at the sorting table is expensive.

What is missing from the account limits how far it can be taken. No carat weight, no measurements, no colour, no price and no country of submission are given, so this desk cannot say whether the stone was a parcel item or a single significant piece, and cannot put a value on what an undetected pass would have cost.

The institute also states that the Gemological Institute of America identified a comparable stone days earlier, and attributes that to a report by IDEX Online rather than to the GIA directly. The claim is hedged twice in the original and is carried hedged here. This desk found no English-language trade coverage of the Israeli test and no GIA statement of its own, and neither absence settles anything either way.