Coloured gemstones testing
Coloured gemstones come in an incredible array of colours and varieties. Emeralds, rubies and sapphires are most well-known, but our testing services and research efforts go far beyond these three varieties. Our expertise in treatment detection and origin determination of coloured gemstones is based on decades of research, a large reference collection and continuously developing new techniques to analyse these treasures of nature.
Get your gems tested by us.
- Single or series of loose coloured gemstones
- Gemstones mounted in jewellery
- Coloured stone bead necklaces
Discover our coloured gemstones reports
For more specific information on disclosure and standards, and issues related to specific coloured gemstones please click on the gem you want to submit for testing.
For any question regarding our testing services, please do not hesitate to contact us.
Colour terms & Colour stability
“Pigeon Blood Red” and “Royal Blue” are famous trade colour terms. Learn how SSEF uses them in color determination. Get also more information about our expertise in detection of heating treatment.
SSEF at auction
55.22 ct ‘Estrela de Fura’ ruby from Mozambique (unheated) mounted in a ring sold at Sotheby’s New York in June 2023 for US$ 34,804,500. Photo: Sotheby’s.
Famous gems tested by us
The Graff ruby, the Aga Khan emerald, the Peacock sapphire necklace or the Sunrise ruby have been tested by the Swiss Gemmological Institute SSEF.
Our testing philosophy
SSEF’s four core values reflect a strong commitment to advancing the science of gemstone testing, maintaining the highest standards, and safeguarding independence. The abbreviation SSEF stands for “Schweizerische Stiftung für Edelstein-Forschung,” or in English: Swiss Foundation for the Research of Gemstones.
Explore our research library
Unsupervised Machine Learning for the Geographic Origin Determination of Cu-bearing Tourmaline
Determining the geographic origin of Cu-bearing tourmaline poses a significant challenge in gemmology, particularly when traditional microscopic methods yield inconclusive results.
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.
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.
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.
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 stones had further been spared any treatments, thus meaning their attributes were entirely natural.
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 homogeneous green colour.
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.
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.
Rare encounter: Sapphire with grandidierite needle inclusion
Recently, the SSEF received for testing a sapphire of pale blue colour with a distinct colourless needle-like inclusion, resembling to some extent long prismatic pargasite needles known in Kashmir sapphires.
Unheated pink sapphire from Madagascar with FTIR bands at 3232 and 3185 cm–1
FTIR spectroscopy has long been used to detect heat treatment of corundum via the presence of specific absorption bands related to structurally bonded hydroxyl groups in corundum.
Väyrynenite of exceptional quality and size, reportedly from Nigeria
Väyrynenite is a rare phosphate mineral that was first discovered in 1935 in a granitic pegmatite near Orivesi in southern Finland.