Purple to bluish grey chalcedony from Ethiopia
In the past 15 years, Ethiopia has repeatedly gained attention for a variety of new gem finds. In 2008, a large deposit of white play-of-colour opal was found (Rondeau et al., 2010), followed by black opal with play-of-colour in 2013 (Kiefert et al., 2014).
Damage caused to gemstones by lasers during jewellery repair
Damage caused to gemstones by lasers during jewellery repair. Journal of the Gemm. Ass. of Hong Kong, Vol. 43, 23-27.
Sapphires Heated with Pressure – A Research Update
Sapphires Heated with Pressure – A Research Update. Published in InColor, Spring 2019, 86-90.
Sapphires from New Zealand
Sapphires from New Zealand. Published in 2006. Author(s): L. Kiefert, M.S. Krzemnicki, G. Du Toit, R. Befi, K. Schmetzer
X-ray luminescence, a valuable test in pearl identification
X-ray luminescence, a valuable test in pearl identification. Published in Journal of Gemmology, 2005. Author(s): H.A. Haenni, L. Kiefert, P. Giese
Asterism in beryl, aquamarine and emerald- an update
Asterism in beryl, aquamarine and emerald- an update. Published in Journal of Gemmology, 2004. Author(s): K. Schmetzer, L. Kiefert, H.A. Haenni
Ein neues Instrument für die analytische Gemmologie: LIBS
Ein neues Instrument für die analytische Gemmologie: LIBS Author(s): H.A. Haenni, M.S. Krzemnicki, L. Kiefert, J.-P. Chalain
Synthetic Verneuil corundum with unusual color zoning
Synthetic Verneuil corundum with unusual color zoning. Published in Gems & Gemology, 2004. Author(s): L. Kiefert
Verschiedenfarbige Bernsteine aus dem Baltikum
Verschiedenfarbige Bernsteine aus dem Baltikum. Published in 2003. Author(s): L. Kiefert
“Rainbow calsilica”
“Rainbow calsilica”. Published in GAHK Journal, 2003. Author(s): L. Kiefert