Scientific Publications
In May, this exceptional brooch handed by Artcurial auction house (thank you for your trust), for an identification of the diamonds, grab LFG’s attention.
The 2 large pear-shaped old-cut diamonds (7.79 ct and 5.90 ct) colours were difficult to describe, a mixture of grey, green and brown. When the scientific analyses highlighted the rare type of these diamonds, our gemmologists were very intrigued.
Indeed, these natural type IIb diamonds, i.e. containing boron, are extremely rare (form at a depth of 670 km between the upper and lower mantle or the top of the lower mantle), and their colours are commonly blue to greyish blue to grey. These 2 large diamonds, graded by the LFG as dark greenish brownish grey and dark greenish grey colour, were therefore of an unusual colour.
In addition, the question arose: were these 2 rare type IIb colored diamonds cut from the same rough diamond?
Aurélien Delaunay, Stefanos Karampelas, Annabelle Herreweghe and Emmanuel Fritsch outline their scientific hypotheses in The Journal of Gemmology n°39-3, 2024 (page 270-275).
Due to its rarity and beauty, this exceptional brooch was adjudicated by Artcurial for 49 850€, in July 2024.
