Exceptional Colour Change Garnets Showing the Usambara Effect
by Dr. M.S. Krzemnicki, first published in Facette 21 (February 2014) Colour change, also known as“alexandrite effect” has been studied extensively since it was first described in 1831 for alexandrite (chromium-bearing variety of chrysoberyl) from Russia (von Pott, 1842). Since then, numerous minerals or g
Gemstones of the Garnet Group – about mixed crystals and solid solution
Gemstones of the Garnet Group – about mixed crystals and solid solution. Published in Journal of the Gemmological Association of Hong Kong GAHK, 2019, Volume XL, 36-49.
Grossular from Tanzania with Uncommon Inclusions
Grossular from Tanzania with Uncommon Inclusions. Published in Journal of Gemmology, 36(6), 500-501.
Yellow danburite from Namalulu, Tanzania, and Myanmar: Origin of Colour and Its Stability
Yellow danburite from Namalulu, Tanzania, and Myanmar: Origin of Colour and Its Stability. Published in Journal of Gemmology, 35, 5, 384-386. Author(s): C.P. Smith, M.S. Krzemnicki
Yellow danburite from Namalulu, Tanzania: Gemmological properties and chemical composition
Yellow danburite from Namalulu, Tanzania: Gemmological properties and chemical composition. Published in Journal of Gemmology, 2017, 35, 5, 381-384. Author(s): C.P. Smith, M.S. Krzemnicki, H.A.O. Wang
Sannan-Skarn, ein neuer Schmuckstein aus Pakistan
Sannan-Skarn, ein neuer Schmuckstein aus Pakistan – Sannan-skarn, a new gemstone from Pakistan. Published in Zeitschrift der Deutschen Gemmologischen Gesellschaft, 2016, 65, 1-2, 41-46. Author(s): H.A. Haenni, L. Franz
Zircon – A very old gemstone
Zircon – A very old gemstone. Published in Journal of Gemmological Association of Hong Kong GAHK, 2016, 37, 37-41. Author(s): H.A. Haenni
Nail-head Spicules as Inclusions in Chrysoberyl from Myanmar
Nail-head Spicules as Inclusions in Chrysoberyl from Myanmar. Published in Journal of Gemmology, 2015, 5, 434-438. Author(s): K. Schmetzer, M.S. Krzemnicki
Saguaro Stone, a New Ornamental Material from Arizona (USA)
Saguaro Stone, a New Ornamental Material from Arizona (USA). Published in Journal of Gemmology, 2015, 7, 567-569.
Olivine – Peridot
Olivine – Peridot. Published in Journal of the Gemmological Association of Hong Kong GAHK, Vol. 35, 35-37. Author(s): H.A. Haenni