Colour change in gemstones is an interesting phenomenon, which can be due to a number of reasons. One of the causes is the so called Usambara effect, a type of colour change which is not so well known in the public. In contrast to the...
Most recently, we received a pearl necklace with 410 pearls strung on three regularly graduated strands. The pearls were characterized by a beautifully matching colour and a fine pearl lustre, reminiscent of ‘classic’ natural pearls from the Arabian Gulf. However, a closer look using X-ray...
SSEF pioneered DNA fingerprinting of pearls in 2013, in collaboration with scientists from ETH Zürich. This was the first published report of oyster DNA extraction from a pearl, allowing us to trace and fingerprint pearls of unknown origin and match them to the specific oyster...
SSEF had the pleasure to add to this eclectic (data) collection the famous sapphire of Catherine the Great, a historic gem from Ceylon (Sri Lanka) of exceptional quality and beauty....
In 2000, SSEF announced that it was able to identify the HPHT treatment of type II diamonds. About 20 years later, this article summarizes how we were able to achieve this breakthrough and which people from the trade and other research institutions were involved in...
As with any gemstone with fissures, it is of no surprise that some Brazilian Paraiba Tourmaline is filled with a colourless foreign substance (mostly artificial resin) to modify and enhance its transparency and thus apparent beauty. ...
Fake pearls are beads (of whatever shape) which have been cut entirely from shell material. A perfect source for the production of such fake pearls is the Tridacna clam, amongst the largest living bivalve mollusc with a massive and thick shell of up to...
Since two years, the SSEF has been working with the Laboratory for Neutron Scattering and Imaging at the Paul Scherrer Institute (PSI) using their ICON beamline (cold neutron imaging) at the SINQ spallation source. The aim of these research projects in collaboration with Dr. Lehmann...
The daily routine at SSEF usually consists of testing rubies, sapphires, emeralds, pearls and diamonds. Although sometimes challenging and interesting, especially taking into account the quality and the documented historical provenance of some of these gems and jewellery items, it is also always of great...
Madagascar, an island of many gem treasures, saw in recent months another ‘sapphire rush’ after the discovery of a new gem deposit about 35 km east of the small town of Ambatondrazaka. ...