Estrela de Fura: an exceptional ruby of 55 ct
On the 8th of June 2023, the Estrela de Fura ruby was sold at Sotheby’s in New York for a world record price of US$ 34.8 million. This ruby of 55.22 ct was cut from a 101 ct piece of rough, discovered in July 2022 near Montepuez in Mozambique, in a mine operated by the Fura Gems company.
Pigeon blood red ruby from Vietnam
Recently, a beautiful Vietnamese ruby of 2.10 ct and vivid red colour was submitted to SSEF for testing. Microscopic observations and chemical trace element analysis confirmed its Vietnamese origin and our colour grading protocol revealed that this stone was well fitting to be called ‘pigeon blood red’ base
Effects of gamma irradiation on ruby and pink sapphire: an update
Gamma irradiation is a treatment method that may enhance the colour and visual appearance of gemstones, such as diamond, topaz, quartz, and corundum, to name a few. This treatment method uses strong gamma rays, either from radioactive isotopes like cobalt-60 (60Co) or from a linear accelerator (LINAC), to induc
Ruby with xenotime inclusion: age dating provides evidence of east african origin
Rubies from marble deposits are chemically rather similar, regardless of whether they originate from marbles in Myanmar, Vietnam, Tajikistan, or even from Tanzania or other countries in East Africa.
Successful dating of zircon inclusion in ruby despite intense heat-treatment
Age dating of zircon inclusions in rubies and sapphires can provide useful information for origin determination. Zircon is a mineral which usually incorporates uranium when it is formed, and this uranium is decaying to lead over time enabling age dating by measuring their ratio.
SSEF jewellery collection: a brooch by René Boivin (1944)
In 2022 the SSEF began its project of establishing a jewellery collection illustrating the history of jewellery to accompany the Advanced History of Jewellery Course held at SSEF (next taking place July 15-19 2024 in Basel). I was thrilled by this visionary approach – and grateful for this unique opportunity
Detection of Low-Temperature Heat Treatment in Corundum: Possibilities and Challenges (2024)
Presentation by Dr. Michael S. Krzemnicki at the GILC conference in Tucson in 2024.
Dehydration of Diaspore and Goethite during Low-Temperature Heating as Criterion to Separate Unheated from Heated Rubies and Sapphires
Dehydration of Diaspore and Goethite during Low-Temperature Heating as Criterion to Separate Unheated from Heated Rubies and Sapphires. Minerals 2023, 13, 1557.
Effects of Gamma Irradiation on Ruby and Pink Sapphire and Potential Detection Methods in Gem Labs
Keywords: Ruby, Pink sapphire, Gamma irradiation, UV-VIS, Raman, R-Line
Phase transformations as important markers for heat treatment detection of corundum and other gemstones (2023)
Presentation by Michael S. Krzemnicki, Pierre Lefèvre, Wei Zhou at the International Gemmological Conference IGC 2023 in Tokyo, Japan.