Recherches
Winza ruby with hollow tube as a helix
In late 2007, a new deposit of rubies was discovered near the village of Winza in central Tanzania, creating quite a stir in the trade due to the quality and vivid colour of these rubies.
Eclogitic orange-yellow diamonds coloured by the 480 nm band
We recently acquired three orange-yellow diamonds for the SSEF collection research. These diamonds immediately retained our attention when we did the UV-vis-NIR spectra to identify the defect at the o
Old cultured pearl necklaces
Recently, the SSEF received three pearl necklaces for testing. Each necklace had a clasp containing diamonds and what appeared to be a sapphire. The pearls were graduated in size, with a small knot se
Fissure filling in spinel
The practice of filling fissures with a colourless substance, such as oil, wax or artificial resin, has been common in the gemstone trade for many decades, if not centuries.
Bachelor thesis on heated blue zircon from different origins
Zircon (ZrSiO4) is a common accessory mineral found in rocks, as well as an inclusion in gemstones, primarily corundum. Zircon is also known as a gemstone in its own right, either colourles
Spectrofluorometer: New instrument at SSEF
We have acquired a new instrument at SSEF: a JASCO FP-8550 spectrofluorometer. A spectrofluorometer is a device that can measure fluorescence excitation and emission spectra.
SSEF GemTrack: Documenting the journey of a gemstone
Launched in 2019, the SSEF GemTrackTM service is asked by more of our clients every year. This tracking service not only documents the journey of a gemstone in time, but is also an attracti
An uncommon artificial resin feature in a brazilian Paraiba tourmaline
Recently, we examined a vibrant Brazilian Paraiba tourmaline weighing approximately 6 carats. One particular internal feature stood out that we found interesting for sharing.
CVD synthetic diamond with colour shift
Last November, the SSEF received an interesting round brilliant colourless (with a greyish tint) diamond of ca. 0.7 ct. mounted on an earring for testing.
Emeralds from the Minas Canaã, Minas Gerais, Brazil
In September 2024, the SSEF had the privilege of testing a few emeralds from the Mina Canaã, some of which exhibited exceptional qualities. Impressive in terms of weight, clarity and colour, these st
Cultured South Sea pearls with small beads
Identifying beaded cultured pearls is usually quite straightforward, as such pearls often contain a large bead made from a freshwater shell with a nacre layer only 1.5 mm or less thick.
Fake it ‘til you break it: Oddities and fraud cases submitted to SSEF
Apart from beautiful and exceptional gemstones, the SSEF also gets from time-to-time submissions which clearly fall far from that prestigious range.
Age dating of burmese jadeite
Recently, the SSEF received a strand of Burmese jadeite jade beads for testing. The beads were slightly graduated with a diameter ranging from 8 to 11 mm and exhibited a beautifully saturated and homo
Purple substance in hollow tubes to mimic unheated Paraiba tourmaline
Recently, the SSEF received a 14-carat, light blue, copper-bearing tourmaline for testing. Based on trace element concentrations, its Mozambique origin was readily established.
Phosphorescence spectrometry of diamonds
The JASCO FP-8550 spectrofluorometer. The instrument has a variety of applications. Here, we report on the phosphorescence lifetime study of a 0.705 ct, round, brilliant-cut, colourless (H/VS1), natur
Study on sapphires with « exotic » elements and implications for heat treatment detection
In a recent study, we analysed a series of unheated gem-quality sapphires containing ‘exotic’ elements such as Sn, Nb, Zr, Ta, W, also known as high-field-strength elements.
Age dating quality control
Knowing the age of a gemstone can be valuable when determining its origins. Unfortunately, most gemstones cannot be dated directly. However, it is possible to determine the age of certain inclusions c
Renaissance point cut diamond and gold ring
Since the beginning of human history, jewellery has been created, with its materials, including gemstones and precious metals, being reused to make new pieces.