Damage caused to gemstones by lasers during jewellery repair
Damage caused to gemstones by lasers during jewellery repair. Journal of the Gemm. Ass. of Hong Kong, Vol. 43, 23-27.
SSEF conducts analysis of cobalt-blue spinel from a newly reported source in Tanzania
For several months already a supply of blue cobalt-bearing spinel has been appearing in the gem trade, including some stones of remarkable size -up to 40 carats- and quality. According to information from reliable sources, the source of the new find is a deposit located about 20 kilometres south-east of Mahenge
News from the SSEF (2022)
Presentation by Dr. Michael S. Krzemnicki at the Swiss Gemmological Society SGG conference in 2022.
Natural pearl necklace with one imitation pearl
Our testing not only revealed the presence of 40 natural pearls of a quite remarkable diameter (8-11 mm), but in addition one imitation pearl consisting of a plastic bead covered by a ‘lacquer’ coating that seeks to mimic a pearly lustre.
Heated spinel from Tajikistan
The spinels were nearly free of any inclusions except for a few tiny colourless forsterite inclusions. In combination with trace element analyses, the origin of these spinels could be unambiguously attributed to the famous spinel mines near Kuh-i-Lal, located in the Pamir mountains in southern Tajikistan, close
The science of gem testing at SSEF: a fascinating tale
Gemmology is a science with its foundations more than a hundred years ago, specifically driven by the emergence of synthetic stones and cultured pearls in the gem trade in the early 20th century.
Visit to the Mong Hsu ruby deposit in Myanmar (Burma)
Mong Hsu is one of the reputed ruby deposits in Myanmar (Burma). It is located about 250km southeast of Mogok, in the Shan State, in northeastern Myanmar.
Diamond fraud uncovered
As in the past, the SSEF is regularly asked by the Swiss police authorities to act as a gemmological adviser in criminal cases. Usually, these are fraud cases, involving undeclared or mislabeled gemstones or their imitations. In a recent case with about 20 stones submitted by the police, we not only found diamo
Pair of sautoirs by René Lalique
René Lalique (1860-1945) was one of the most ingenious and creative designers of jewellery and glass objects at the end of the 19th and beginning of the 20th century. He significantly contributed to the Art Nouveau and Art Déco periods.
Gemmological study of the medieval Königsfelder diptychon
In 1298 AD, the king of Hungary Andreas II presented to his wife Queen Agnes a stone-set wooden altar piece as a royal wedding present. This small medieval artwork, known today as the Königsfelder diptychon, was originally made in Venice.