Coloured gemstones
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.
We test different types of coloured stones
- Single or series of loose coloured gemstones
- Gemstones mounted in jewellery
- Coloured stone bead necklaces
For more specific information on disclosure and standards, and issues related to specific coloured gemstones please visit the Understand SSEF Reports page, which offers extensive details on individual varieties of gemstones.
Explore our research library
Paraiba or Not? Cu-bearing Tourmaline with a Distinct Fe Concentration
Paraiba or Not? Cu-bearing Tourmaline with a Distinct Fe Concentration. Published in Journal of Gemmology, 2022, 38 (1), 20-22.
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 Tajik
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.
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 This small medieval artwork, known today as the Königsfelder diptychon, was originally made in Venice.
A never-ending story: recheck service and report validity check on myssef.ch for emeralds
Imagine life as an emerald. Just born in the rocks and growing, you get joggled and bruised by mother nature and later by the mining process. So, already in your young age you carry quite some scars and fractures, which reduce your true beauty considerably and may not make it so easy to find a good
Zircon inclusion analysis for sapphire origin determination
Zircon ZrSiO₄ a very intriguing mineral, not only because it can be used as an attractive gemstone (Figure 1) but also due to the fact that it can contain minute traces of radioactive elements (U, Th), which decay over time to lead (Pb) isotopes.
Beware of synthetic ruby with ‘zircon-like’ cluster inclusions
Very recently, we tested a tricky case of a synthetic ruby (Figure 1) of 4.27 ct, submitted to SSEF as a natural stone accompanied by two lab reports confirming its natural origin. Under the microscope, the submitted stone showed ‘zircon-like’ cluster inclusions (Figure 2). They were somehow rem
New copper-bearing tourmalines from Nigeria
Copper-bearing tourmaline from Nigeria is known in the trade since about two decades (Milisenda 2001, Henricus, 2001; Smith et al., 2001; Zang et al., 2001). The first reported material from Nigeria was rather of aquamarine- to amethyst-like colours, but shortly after it was followed by a limited an
To be, or not to be, that is the question: chrysoberyl versus alexandrite
The mineral chrysoberyl BeAl₂O₄ is a highly appreciated gemstone due to its rarity, brilliance, and beauty and comes in attractive colours commonly ranging from colourless (chemically pure) to yellow, yellowish green, green, and brownish green to dark brown, mostly related to the presence of iro
Dyed corundum from Burma
by Dr. M.S. Krzemnicki, first published in Facette 27 (June 2021) It cannot be repeated often enough: any gemstone which contains fissures is prone to be treated with fissure filling substances, either by using a colourless or coloured substances (e.g. oil). Even when the stone comes from
Canary tourmaline from Zambia
by Dr. M.S. Krzemnicki, first published in Facette 27 (June 2021) Tourmaline is a mineral group of complex boro-silicates and is well known to produce gemstones in a wide range of beautiful colours. A specifically attractive variety is vivid yellow elbaite tourmaline, which owes its colour
A gemmologist’s delight: poudretteite, musgravite, taaffeite, and grandidierite
by Dr. M.S. Krzemnicki, first published in Facette 27 (June 2021) In recent months, the SSEF received again a number of very rare collector stones for testing. These included poudretteite, musgravite, taaffeite, and grandidierite of exceptional quality. Poudretteite, ideally KNa2B3Si12O30,