Publications with abstracts of some more recent papers

Abstract: Three historical ‘asteriated’ diamond slices present mixed-habit growth with contemporaneous lobe-shaped cuboid sectors and octahedral sectors. The lobe shape is explained by continuous variation of the relative growth rates. Nitrogen concentration in octahedral sectors is higher than in cuboid sectors, whereas hydrogen is incorporated mostly in cuboid sectors. The H-related IR peak at 3236 cm-1 peak, and the two peaks at 3050 and 3154 cm-1 (which may be completely absent from the spectra) are independent from the well-known 1405–3107 cm-1 system. Nitrogen aggregation during thermal history seems partially inhibited in cuboid sectors by the large amount of hydrogen, as platelets and N3 centres are present in octahedral sectors but not in cuboid sectors. Cuboid, H-rich growth sectors are thought to appear when the amount of hydrogen in the medium is too high to be incorporated in the octahedral sectors only. The definition of ‘H-rich diamonds’ is revisited. The first-order Raman peak at 1332 cm-1 is slightly growth-sector dependent; cuboid sectors show a sharper and more Lorentzian peak than octahedral sectors.

Kiefert, L., McLaurin Moreno, D., Arizmendi, E., Hänni, H.A. & Elen, S. (2004): Cultured Pearls from the Gulf of California, Mexico. Gems & Gemol. 40, 26-38.

Abstract: Black pearls have been found in Mexico's Gulf of California since the area was settled more than 2000 years ago. Attempts at culturing pearls in this area have met with varying success over the past century. Today, a pearl farm in Guaymas is producing commercial quantities of mabe as well as bead-nucleated full-round cultured pearls from the indigenous pearl oyster Pteria sterna. This article provides an overview of the history of natural and cultured pearls from Mexico, describes pearls culturing at the Guaymas farm, and focuses on the properties of bead-nucleated cultured pearls from the P. sterna. These cultured pearls have a brown or gray to dark gray bodycolor with various interference colors causes by the stacking of platy aragonite crystals and organic matter. One indication of their natural color (and their Mexican provenance) is a red fluorescence to long-wave UV radiation.

Hänni, H.A. (2004): Black horn coral coated with artificial resin. - . Gems & Gemology, Gem News International, Vol. 40, No. 1, 78-79.

Hänni, H.A. (2004): Der Diamant. - RohmZeit 1/04, 12-14.

Hänni, H.A. (2004): Zirkon ist nicht Zirkonia. - RohmZeit 1/04, 22-23.

Hänni, H.A. & Krzemnicki, M.S. (2004): Pezzottaite, a new mineral and gem (supplement to 'Caesium-rich morganite from Afghanistan and Madagascar'). J. Gemm., Vol. 29, 75-76.
Abstract: Nomenclature used to describe new pink mineral specimens from Afghanistan and Madagascar is brought up to date. Structural differences between beryl and pezzottaite are illustrated.

Schmetzer, K., Kiefert, L. & Hänni, H.A. (2004): Asterism in beryl, aquamarine and emerald - an update. J. Gemm., Vol. 29, 65-71.

Abstract: An overview about present knowledge of asterism in beryl, aquamarine and emerald is presented. A bronze-brown beryl from Brazil and several aquamarines from Madagascar revealing six-rayed asterism were examined. An emerald specimen from Madagascar showing four- and six-rayed stars is studied in detail. The asterism of this specimen is due to a combination of a six-rayed star emerald and an emerald cat's-eye. Three causes for six-rayed stars in various members of the beryl family are known: (a) needle-like mineral inclusions, (b) elongated thin fluid films and (c) elongated negative crystals.

Hänni, H.A. (2004): Ein notwendiger Test in der Perlenuntersuchung. Z. Dt. Gemmol. Ges. 53/1, 39-42.

Abstract: The increasing similarity of structures encountered in natural pearls and non nucleated freshwater cultured pearls requires an additional criterion for the differenciation. The majority of natural pearls are from saltwater oysters, contrarily to this the non-nucleated cultured pearls are from freshwater mussels. Since long it has been known that freshwater pearls produce a luminescence reaction under x-rays, not so saltwater pearls. The reason is because freshwater nacre contains a higher amount of manganese traces. By using a sensitive camera this visible luminescence can be recorded and displayed on a monitor. The beads (from freshwater nacre) in Japanese saltwater cultured pearls (Akoya) also react on the x-rays excitation and shine through the usually thin overgrowths. This enhances the utility of the method for the detection of freshwater pearls. The method is used as an additional test and not an alternative for x-ray shadow pictures.

Hänni, H.A. & Krzemnicki, M.S. (2004): Pezzottait – ein neues Mineral. Supplement to „Caesium-rich morganite from Afghanistan and Madagascar“. Z.Dt. Gemmol. Ges. 53/1, 3-4.

Hänni, H.A., Kiefert, L., Chalain, J.P. & Krzemnicki, M.S. (2004): Are new sapphires from Sri Lanka diffusion-treated or not? Jewellery News Asia, March 2004, 88-90.

Kiefert, L., Hänni, J., Vandenabeele, P., Moens, L. & Hammer, V.M.F. (2003): Der Stein des Regenbogens: „Rainbow-Calsilica“. Z. Dt. Gemmol. Ges. 52/4, 151-162.

Chalain, J.-P. (2003): Spectroscopic study of a yellowish green HPHT synthetic diamond. Journal of the Gemmological Association of Hong Kong. Vol. 24, 61 - 67.

Kiefert, L. (2003): Rainbow Calsilica. Journal of the Gemmological Association of Hong Kong. Vol. 24, 41 - 46.

Abstract: An ornamental stone with bands in various colours was investigated with traditional gemmological as well as sophisticated analytical methods. The analysis of the various colours with Raman spectroscopy showed that the material was not of natural origin, as stated by the vendors, but an artificial product, partly coloured by artificial pigments. The material is stabilised using a waxy / resinous material.

Hänni, H.A., & Krzemnicki, M.S. (2003): Pezzottaite - a new mineral. Journal of the Gemmological Association of Hong Kong. Vol. 24, 23 - 32.

Häberli, S., Kiefert, L. (2003): Nulla parte mirabilior. Zur Verwendung von Edelsteinen in der Antike, Seite 30 - 34. In: Willers, D., Raselli-Nydegger, L.: Im Glanz der Gˆtter und Heroen, Verlag Philipp von Zabern, Mainz am Rhein, Deutschland.

Krzemnicki, M.S., Bosshart, G. (2003): Der Binntal Smaragd als Juwel & L'Èmeraude du Binntal en tant ue bijoux. - Schweizer Strahler, vol. 13, No. 4, 31 - 33 & 12 - 14.

Kiefert, L. (2003): Verschiedenfarbige Bernsteine aus dem Baltikum. - Rohm Zeit, No. 4, Nov. 2003, 20 - 21.

Kiefert, L. (2003): Synthetic spinel with unusual inclusions. Gems & Gemology, Gem News International, Vol. 39, No. 3, 239 - 240.

Hänni, H.A., Koivula, J.I., & Tannous, M. (2003): Star sunstone from Tanzania. Gems & Gemology, Gem News International, Vol. 39, No. 3, 235 - 236.

Kiefert, L. (2003): An unusual star quartz. Gems & Gemology, Gem News International, Vol. 39, No. 3, 234 - 235.

Hänni, H.A. (2003): New morganite deposit in Madagascar. Jewellery News Asia, June 2003, 58 - 60.

Hänni, H.A., Krzemnicki, M.S. (2003): Caesium-rich morganite from Afghanistan and Madagascar. J. Gemm., Vol. 28, No. 7, 417 - 429.

Abstract: Quite saturated pink beryl of Madagascar and Afghanistan are described. They display densities between 2.91 and 3.10 g/cm3 and RI values up to 1.608 (ne) and 1.615 (no) which exceed the values reported so far in the literature. Chemical analyses reveal very high caesium concentrations (up to 15.18 wt.% Cs2O). the incorporation of Cs in the structural channels of beryl is mainly coupled with a substitution on the tetrahedrally-coordinated beryllium site. Such stones belong to the so-called tetrahedral beryls. UV-Vis-NIR spectra show manganese and water absorption features typical for morganite. XRD data and Raman spectra reveal a distinct increase in cell parameters (mainly c0) compared to pure beryl, thus underlining the unusual character of the studied material. While the sample from Afghanistan is semi-transparent, transparent stones are found among the samples from Madagascar. Inclusions consist mainly of fine tubes parallel to the c-axis, flat fluid-filled inclusions parallel to the basal pinacoid, and tension fractures. Based on chemical composition, spectral data and colour saturation we suggest that the simple term morganite be retained to describe the stones, unless a new term is approved by the IMA to recognize the extraordinary composition and structure of the material.

Hänni, H.A., Krzemnicki, M.S. (2003): Cäsiumreiche Morganite aus Afghanistan und Madagaskar. Z. Dt. Gemmol. Ges. 52/2-3, 67 - 80.

Hänni, H.A. (2003) Die Quarzgruppe - eine knappe ‹bersicht. RohmZeit 2/03, Mai 2003, 20 - 21.

Fritsch, E., Chalain, J.-P., Hänni, H., et al. (2003) Le nouveau traitement produisant des couleurs orange ‡ jaune dans les saphirs. Revue de Gemmologie AFG No. 147, 11-23

Chalain, J.-P. (2003): A type IaB diamond showing a "tatami" strain pattern. Gems & Gemology, Gem News International, Vol. 39, No. 1, 59 - 60.

Schmetzer, K., Burford, M., Kiefert, L., & Bernhardt, H.-J. (2003): The first transparent faceted grandidierite from Sri Lanka. Gems & Gemology, Vol. 39, No. 1, 32 - 37.

Abstract: Gemological, chemical, and spectroscopic properties are presented for the first known transparent faceted grandidierite. This jewelry-quality 0.29 ct stone was fashioned from rough reportedly found in the Kolonne area of Sri Lanka. The greenish blue borosilicate has refractive indices of 1.583 to 1.622, which correlate to a low iron content of 1.71 wt.% FeO and readily separate it from the gem material closest in properties, lazulite.

Smith, C.P., Bosshart, G., Graeser, S., Hänni, H.A., Günther D.,Hametner, K., & Gübelin, E. (2003): Poudretteite: a rare gem species from the Mogok valley, Gems & Gemology, Vol. 39, No. 1, 24 - 31.

Abstract: In 2000, an unfamiliar gemstone was purchased in Mogok. It subsequently proved to be the rare borosilicate poudretteite, a mineral that previously had been identified only as tiny crystals from Mont Saint-hilaire, Quebec, Canada. This article presents a complete gemological description of this unique gemstone and furthers the characterization of this mineral by advanced spectroscopic and chemical analytical techniques.

Krzemnicki, M.S. (2002): Orange topaz with synthetic hematite coating. Gems & Gemology, Gem News International, Vol. 38, No. 4, 364 - 366.

Kiefert, L., Vandenabeele, P. & Hänni, J. (2002): "Rainbow Calsilica". - In: Laurs, B. (Ed): Gem News International, Gems & Gemology. Vol. 38, No. 4, 360-362.

Hänni, H.A. (2002): Spinel crystal with an unusual shape. Gems & Gemology, Gem News International, Vol. 38, No. 4, 355.

Hänni, H.A. (2002): Pearls. – In: Magnificent Jewels. Catalogue of the November 19, 2002 Geneva Auction, Phillips de Pury & Luxembourg, 107-108.

Hänni, H.A. & Pettke, T. (2002): Eine neue Diffusionsbehandlung liefert orangefarbene und gelbe Saphire. - Z. Dt. Gemmol. Ges. 51, 137-152.

Abstract: A new kind of orange coloured sapphires has appeared in masses on the marketplace in 2001. Soon it was detected that many of the stones, which were treated in Thailand, had an artificial colour distribution, characterized by a variably thick layer of yellow to orange colouration parallel to the cut surface. It became evident that the original corundum originating mainly from Songea (Tanzania) or Ilakaka (Madagascar) was heat treated together with foreign substances. Classical gemmological investigations cannot reveal the treated nature where a colour rim is not visible. UV-Vis spectrometry may show evidence of trapped hole colour centres as created by divalent ions. Laser-ablation inductively-coupled plasma mass spectrometry (LA-ICPMS) revealed the presence of a diffusion treatment in which beryllium plays an important role in creating the new colour. LA-ICPMS has demonstrated that the beryllium content of untreated and simply heat treated corundum is below the detection limit (approx. 1 ug/g) of samples inspected, whereas concentrations of 10-15 ug/g are typical for the new material. Original trace element compositions in the natural material strongly influences the success of the diffusion treatment. The terminology of the new material is internationally debated and represents an identification problem in that the diffusion of beryllium may completely penetrate a stone. The consideration of a variety of trace elements including those which do not directly participate in colour forming may deliver reliable proof in determination of heat and diffusion treatment in corundum.

Hänni, H.A. (2002): Orange Treated Sapphire - Towards Finding a Name for a New Product. - J. Gemmol. Assoc. Hong Kong 23, p. 23-28.

Kiefert, L. (2002): Zuchtperlen vom Golf von Kalifornien, Mexiko. - Z. Dt. Gemmol. Ges. 51/2-3, 121-132.

Schmetzer, K., Hainschwang, T., Kiefert, L. & Bernhardt, H.-J. (2002): Rosa bis rosa-orangefarbene Malaya-Granate aus Bekily, Madagaskar. - Goldschmiedezeitung No. 6, 80-85.

Schmetzer, K., Hainschwang, T., Bernhardt, H.-J. & Kiefert, L. (2002): New Chromium- and Vanadium-Bearing Garnets from Tranoroa, Madagascar. - Gems & Gemology 38, No. 2, 148-155.

Abstract: Pyrope-spessartine garnets from Tranoroa, in southern Madagascar, contain appreciable Cr and somewhat lower V contents. Although these elements are responsible for the color-change behavior of similar garnets from the nearby Bikily area, the Tranoroa samples show only a slight change in color appearance from day or fluorescent light (brownish purple-red) to incandescent light (purplish red). Characteristic internal features in the Tranoroa garnets include networks of rutile needles and strain patterns caused by anomalous double refraction. Additional inclusions are graphite, quartz, negative crystals, apatite, zircon, and monazite. One Cr-bearing spessartine from the same area is also described.

Kiefert, L. (2002): Emerald Treatments. The processes and how to recognize them. - In: Emeralds of the World, ExtraLapis English No. 2, 79-81.

Chalain, J-P. (2002): La certification des diamants de type II. - Revue de Gemmologie AFG No. 145/146, 37-39.

Kiefert, L., Schmetzer, K. & Hänni, H.A. (2002): Russian synthetic moissanite. - Ed.: Jehlicka, J. & Kühn, J.: Georaman 2002, 5th International Conference on Raman Spectroscopy Applied to the Earth Sciences, Prague, Czech Republic, June 12-15, 2002. - In: Acta Universitatis Carolinae Geologica 46, 1, 40-41.

Fritsch, E., Rondeau, B., Notari, F., Michelou, J.-C., Devouard, B., Peucat, J.-J., Chalain, J-P., Lulzac, Y., de Narvaez, D. & Arboleda, C. (2002): Les nouvelles mines d'Èmeraude de La Pita (Colombie, 2e partie. - Revue de Gemmologie AFG No. 144, 13-21.

Schmetzer, K., Bernhardt, H.-J., Kiefert, L. (2002): Star garnets and star garnet cat's-eyes from Ambatondrazaka, Madagascar. - J. Gemm. 28, 1, 13-23.

Abstract: Mineralogical and gemmological properties of star garnets from Ambatondrazaka, Madagascar, are given. All samples examined are intermediate members of the almandine-spessartine series with an appreciable pyrope component. Asterism is caused by a dense network of rutile needles that are orientated parallel to the three-folg axes of the cubic garnet hosts. In addition to the white four-rayed stars, reddish-brown cat's-eyes are present in two garnet cabochons. This additional light band is caused by orientated sillimanite lamellae. The formation of different four- and six-rayed stars in garnets is discussed.

Schmetzer, K., Hainschwang, T., Kiefert, L. & Bernhardt, H.-J. (2001): Pink to Pinkish Orange Malaya Garnets from Bekily, Madagascar. - Gems & Gemology 37, No. 4, 296-308.

Abstract: Malaya garnets from Bekily, Madagascar, are predominantly pink to pinkish orange, with some stones orange to red. Discovered only in the late 1990s, the majority are intermediate members of the pyrope-spessartine series with variable contents of almandine and subordinate grossular. The refractive index, specific gravity, and color of these garnets are related to their iron and manganese contents. Inclusions identified by Raman analysis are rutile needles and platelets, graphite, quartz, apatite, zircon, and sillimanite. Negative crystals were also seen. Important differences in predominant color and chemistry were noted when the Bekily garnets, only the second commercial source of malaya garnet, were compared to malaya garnets from East Africa, which have been available since the late 1970's.

Fritsch, E., Chalain, J.-P., Hänni, H. (2001): Identification of GE POL™ Diamonds. - Australian Gemmologist Vol. 21, 172-177.

Hänni, H.A. (2001): Beobachtungen an hitzebehandeltem Rubin mit künstlicher Rissheilung.- Z.Dt.Gemmol.Ges. 50/3, 123-136.

Kiefert, L. (2001): Behandlungen von Smaragd. - Extra Lapis No. 21, Smaragde der Welt, 79-81.

Kiefert, L., Schmetzer, K. & Hänni, H.A. (2001): Synthetic moissanite from Russia.- J.Gemmol.27, 8, 471-481.

Abstract: Five faceted yellow, green, bluish-green and bluish-brown synthetic moissanites of Russian production are described. Polytypism is characterized by Raman spectroscopy. Gemmological properties as well as chemical and spectroscopic properties in the UV-visible range are given. The samples were found to be of 6H- as well as 4H-SiC single crystals, and the variable coloration is caused by various amounts of nitrogen in the lattice of the synthetic moissanites. The criteria already described for the distinction of colourless Americal synthetic moissanites from diamonds in general also apply for a microscope characterization of Russian samples, especially to distinguish them from coloured diamonds.

Hänni, H.A. (2001): Ruby heat treatment and fracture repair.- Jewellery News Asia, November, 75-76.

Kiefert, L., Hänni, H.A. & Ostertag, T. (2001): Raman Spectroscopic Applications to Gemmology. In “Handbook of Raman Spectroscopy“, I.R.Lewis & H.G.M.Edwards (Editors), Marcel Dekker, Inc. New York Chapter 11, 469-489.

Hänni, H.A. (2001): Eine neue Lichtquelle von kurzwelligem UV-Licht für den SSEF IIa Diamond Spotter™ zum Nachweis des Diamanttyps IIa. - Z. Dt. Gemmol. Ges., Vol. 50, 57-58.

Hänni, H.A., Milisenda, C.C. & Henn, U. (2001): Rubine aus neuen Vorkommen in Madagaskar.- Z.Dt.Gemmol.Ges. 50/2, 89-94

Krzemnicki, M.S., Hänni, H.A. & Reusser, E. (2001): Colour change garnets from Madagascar: comparison of colorimetric with chemical data.- J.Gemm. 27, 7, 395-408.

Abstract: In this study 24 colour-change garnets from Madagascar have been studied to gain data for a correlation between chemical composition and colorimetric calculations. All samples belong to the pyrope-spessartine solid solution series. They contain some traces of vanadium (0.27 to 1.61 wt% V2O3), which is responsible for the colour-change in these garnets. Based on visual observations, the investigated samples were separated into five groups of different colour-change behaviour when examined under daylight and incandescent light. Generally, most garnets changed from bluish-green in daylight to purple in incandescent light, although some changed from yellowish-green to pink and brownish-green to brownish-red. Two samples remained almost unchanged, i.e. blue and brown respectively. The visual separation in five groups is consistent with differences obtained by colorimetric calculations. The colorimetric calculations are presented in the CIELab colour space. Comparing colour behaviour with chemical analyses results in a correlation with several intrinsic chemical factors, mainly vanadium, chromium, manganese, magnesium and iron.

Hänni, H.A. (2001): Wissenswertes über Edelsteine.- gold’or 2/01, 141-143

Hänni, H.A., Wu, Shun Tien, Xinqiang, Yuan & Wen-Po, Tsai (2001): A glass imitation of blue chalcedony.- J.Gemm. 27, 5, 275-285.

Hänni, H.A. (2001): Les principes de base du traitement des Èmeraudes. - Revue de Gemmologie No. 141/142, 33.

Chalain, J-P., Fritsch, E. & Hänni, H.A. (2001): Diamants de type IIa et traitement HPHT: Identification. - Revue de Gemmologie No. 141/142, 50-53.

Abstract: Brown diamonds of type IIa may be treated at high Pressure and High Temperature to make them colourless. The gemmological properties of type IIa diamonds are described. Some of the criteria that enable the identification of the colourless HPHT treated diamonds of type IIa are presented hereby.

Schmetzer, K., Gübelin, E., Bernhardt, H.-J. & Kiefert, L. (2000): Oriented inclusions in spinels from Madagascar. - J. Gemm. 27, 4, 229-232.

Kiefert, L., Hänni, H.A. & Chalain, J-P. (2000): Identification of gemstone treatments with Raman Spectroscopy. - Optical Devices and Diagnostics in Materials Science. Andrews, D.L., Asakura, T., Jutamulia, S., Kirk, W.P., Lagally, M.G., Lal, R.B. & Trolinger, J.D. (Eds.): Proceedings of SPIE Vol. 4098241-251.

Kiefert, L. & Hänni, H.A. (2000): Gem-Quality Haüyne from the Eifel District, Germany.- Gems & Gemology, Fall, 246-253.

Kiefert, L. (2000): Hauyn aus der Eifel - ein attraktiver Edelstein. - Z. Dt. Gemmol. Ges. 49, 2, 103-114.

Schmetzer, K., Kiefert, L. & Bernhardt, H.-J. (2000): Purple to purplish red chromium-bearing taaffeites.- Gems & Gemology, Spring, 50-59.

Chalain, J-P., Fritsch, E. & Hänni, H.A. (2000): Detection of GE POL treated diamonds. - Poster presented at various trade shows and conferences.

Chalain, J.-P. , Fritsch, E. & Hänni, H.A. (2000): Zur Bestimmung von GE POL Diamanten: erste Erkenntnisse.- Z.Dt.Gemmol.Ges., 49, 1, p. 19 - 30

Chalain, J.-P. , Fritsch, E. & Hänni, H.A. (2000): Identification of GE POL diamonds: a second step.- J. Gemmol. 27, 2, 73-78.

Chalain, J-P. (1999/2000): Update on Moissanite Identification. - J. Gemmol. Assoc. Hong Kong 21, 12-15.

Hänni, H.A. (1999/2000): Diamanten. - HuberMagazin No. 14, 20-21.

Krzemnicki, M.S. (1999): Diopside Needles as Inclusions in Demantoid Garnet from Russia: A Raman Microspectrometric Study. - Gems & Gemology, 35, No. 4, 192-195.

Hänni, H.A. (1999): Les grenats gemmes.- Revue de Gemmologie No 138/139,16-20.

Chalain, J-P. (1999): Mise ‡ Jour sur la DÈtermination des Substances de Remplissage dans les Emeraudes. - Revue de gemmologie a.f.g. 138/139, DÈcembre, 18-21.

Schmetzer, K., Kiefert, L. & Bernhardt, H.-J. (1999): Multicomponent inclusions in Nacken synthetic emeralds. - J. Gemmol. 26, 487-500.

Kiefert, L, Hänni, H.A., Chalain, J.P. & Weber, W. (1999): Identification of filler substances in emeralds by infrared and Raman spectroscopy. - J.Gemmol.26, 8, 501-520.

Chalain, J.-P. , Fritsch, E. & Hänni, H.A. (1999): Detection of GE POL diamonds: a first stage.- Revue de Gemmologie a.f.g. no 138/139, 8-11

Chalain, J.-P. , Fritsch, E. & Hänni, H.A. (1999): DÈtection des diamants GE POL: une premiËre Ètape.- Revue de Gemmologie a.f.g. no 138/139, 2-7

Chalain, J-P. & Krzemnicki, M.S. (1999): Synthetischer Moissanit und Diamant: Sichere Unterscheidung mit Hilfe des Reflektometers. - Z. Dt. Gemmol. Ges. 48, 2, 77-84.

Hänni, H.A. (1999): Sur la formation de nacre et de perles.- Revue de gemmologie a.f.g. 137, Juin, 30-36.

Hänni, H.A. (1999): Fracture Filling in Emerald and its Detection with Laboratory Methods. - Canadian Gemmologist, Vol. 20, No. 3, 83-86

Schmetzer, K., Zhang, Beili, Gao, Yan, Bernhardt, H.J. & Hänni, H.A. (1999): Element mapping of Trapiche rubies.- J.Gemm. 26, 5, 289-301.

Kiefert, L. & Schmetzer, K. (1998): Distinction of Taaffeite and Musgravite. - J. Gemm. 26, 3, 165-167.

Schmetzer, K. & Kiefert, L. (1998): Zur Färbung von Igmerald (synthetischer Smaragd, hergestellt von der IG. Farbenindustrie). - Goldschmiedezeitung, in Vorbereitung, Sommer 1998.

Schmetzer, K. & Kiefert, L. (1998): The colour of Igmerald (I.G. Farbenindustrie flux-grown synthetic emerald). - J. Gemm. 26, 64 - 84.

Hänni, H.A. (1998): Fracture filling in emeralds and its detection with laboratory methods.- ICA Gazette, Gem News, July/August 5-7; The Singaporean Gemologist, Vol. 5, No. 2, 71-74.

Hänni, H.A. (1998): Short notes on some gemstone treatments.- J.Gemm.Assoc.Hong Kong, Vol.XX, 44-52

Hänni, H.A., Schubiger, B., Kiefert, L. & Häberli, S. (1998): Raman investigations on two historical objects from Basel cathedral: the reliquary cross and Dorothy monstrance.- Gems & Gemmology, summer, 102 -114.

Chalain, J.-P., Hänni, H.A., & Kiefert, L. (1998): DÈtermination des substances de remplissage dans les Èmeraudes.- in ”L’Emeraude”, Association FranÁaise de Gemmologie, Paris.

Schmetzer, K., Kiefert, L., Bernhardt, H.J., Zhang, B. (1997): Im Hydrothermalverfahren gezüchtete synthetische Smaragde aus China. Goldschmiedezeitung, Teil 1: Mai 1998, Teil 2: Juni 1998 (im Druck)

Schmetzer, K., Kiefert, L., Bernhardt, H.J., Zhang, B. (1997): Characterization of Chinese Hydrothermal synthetic Emerald. Gems & Gemology, Vol. 33, No. 4, 276 - 291.

Hänni, H.A. (1997): ‹ber die Bildung von Perlmutter und Perlen.- Z.Dt.Gemmol.G es. 46/4, 183-196

Schmetzer,K, Hänni,H.A. , Bernhardt,H.-J. & Schwarz,D. (1997): Trapiche-Rubine.- Deutsche Goldschmiede-Zeitung, Vol. 95, 11, 107-112.

Hänni, H.A., Kiefert,L., Chalain, J-P. & Wilcock, I.C. (1997): A Raman microscope in the gemmological laboratory: first experiences of application.- J. Gemmol. 25, 6, 394 - 406.

Kiefert, L. & Hänni, H.A. (1996): Detection of fissure fillings in emeralds using a Raman microscope. - Proc. 2nd Australian Conference on Vibrational Spectroscopy, 2-4 October 1996, Queensland University of Technology, Brisbane, Australia, p. 73-74.

Kiefert,L., Hänni,H.A., & Chalain,J-P. (1996): First experiences of application: A Renishaw Raman Microprobe in the gemmological laboratory.- GEORAMAN-96, Institut des MatÈriaux de Nantes, Nantes, France, 10-12 June 1996. In: Terra abstracts. Abstract supplement No. 2 to TERRA nova, Vol. 8, p. 19.

Kiefert, L. & Schmidt, S. Th. (1996): Some Tanzanite Imitations. - Gems & Gemology, Vol. 32, No. 4, p. 270-276.

Schmetzer, K., Hänni, H.A., Bernhardt, H.J. & Schwarz D. (1996): Trapiche rubies.- Gems & Gemology, Winter, 242-250.

Kiefert, L., Hänni, H.A. & Chalain, J-P. (1996): Various applications of a Raman microscope in a gemmological laboratory. - Proc. 2nd Australian Conference on Vibrational Spectroscopy, 2-4 October 1996, Queensland University of Technology, Brisbane, Australia, p. 202-203.

Kiefert, L., Schmetzer, K., Krzemnicki, M.S., Bernhardt, H.J. & Hänni, H.A. (1996): Ein neues Saphirvorkommen im Süden von Madagaskar.- (Deutsche) Goldschiedezeitung, 9/96, 89 - 91 , Forts. 11/96, 73 - 77.

Kiefert, L., Schmetzer, K., Krzemnicki, M.S., Bernhardt, H.J. & Hänni, H.A. (1996): Sapphires from Andranondambo area, Madagascar.- J. Gemm. 25, 3, 185 - 209.

Hänni,H.A., Kiefert,L. & Chalain,J-P. (1996): First experiences of application: A Renishaw Raman microscope in the gemmological Laboratory. - Jewelry Circle's Magazine, 40, 82 - 86.

Hänni,H.A., Kiefert,L. & Chalain,J-P. & I.C. Wilcock (1996): Ein Renishaw Raman Mikroskop im gemmologischen Labor: Erste Erfahrungen bei der Anwendung.- Z.Dt.Gemmol.Ges. 45/2, 55 -70.

Krzemnicki,M.S. & Hänni,H.A., Guggenheim, R. & Mathys, D. (1996): Investigations on sapphires from an alkali basalt, South West Rwanda.- J. Gemm. 25, 2, 90 - 106.

Hänni,H.A., Kiefert,L. & Chalain,J-P. (1996): How to identify fillings in emeralds using Raman spectroscopy.- Jewellery News Asia, September, 154 - 156.

Hänni,H.A. (1996): Raman microprobe fingerprints fillings.- Thailand Jewellery Revue, 9/1, January, 42 -45.

Hänni,H.A. (1995): A short synopsis of pearls: Natural, cultured, imitation.- J. Gemm. Ass. Hong Kong, XVIII, 43 - 46.

Kammerling, R.C., Koivula, J.I, Johnson, M. et al. (1995): Gem News: The 25th International Gemmological Conference Thailand).- Gems & Gemology, Winter, 271 -287.

Hänni,H.A. & Kiefert,L. (1995): AGEE hydrothermal synthetic emeralds.- Schweizer Uhren- und Schmuckjournal, 294-297 (D, F, E, Sp)

Hänni,H.A., Schmetzer,K. & Bernhardt,H.-J. (1995): Douros synthetic ruby - a new challenge to gemologists.- Jewelry Circles Magazine, 34, 80-85, in Chinese.

Hänni,H.A., Schmetzer,K. & Bernhardt,H.-J. (1994): Synthetische Rubine von Douros: Eine Herausforderung für den Gemmologen.- (Deutsche) Goldschmiede-Zeitung, 11, 101-108.

Hänni,H.A. & Kiefert,L. (1994): AGEE hydrothermal synthetic emeralds.- Jewel Siam Oct./Nov. 80-85.

Gutmannsbauer,W. & Hänni,H.A.(1994): Structural and chemical investigations on shells and pearls of nacre forming salt- and freshwater bivalve molluscs.- J.Gemm. 24, 4, 241-252.

Hänni,H.A. & Schmetzer (1994): How to identify Douros synthetic rubies. - Jewellery News Asia, September, 156-168.

Hänni,H.A., Schmetzer,K. & Bernhardt,H.-J. (1994): Synthetic rubies by Douros: A new challenge for gemologists.- Gems & Gemology, Summer, 72-86.

Hänni,H.A. (1994): Origin determination for gemstones: possibilities, restrictions, and reliability.- J.Gemm. 24, 3, 139-148.

Gutmannsbauer,W., Lüthi,R., Reimann,P., Hänni,H.A. & Haefke,H. (1994): SFM Provides New Instight in Biomineralization Processes.- in NATO workshop on "Forces in Scanning Probe Methods", NATO Advanced Study Institute, (ASI) 7-18 March 1994, Germany.

Hänni,H.A. (1993): Spectroscopy and its application in gemmology. J. Gemm. Assoc. Hong Kong, 16, 16-22.

Hänni,H.A. (1993): Why epoxy-filled emeralds must be accepted.- ICA Gazette, April, p. 11

Hänni,H.A. (1993): Origin determination for gestones: Possibilities, Restrictions, Reliability. - Jewelry Circle's Magazine, 26, 94-97 in Chinese

Hänni,H.A. (1993): Hydrothermal synthetic emeralds from Australia: Emeralds and pink beryls.- Swiss Watch & Jewelry Journal, 1/1993, 133-136.

Hänni,H.A. (1993): Identification of fissure-treated gemstones.- The Journal of the Gemmological Association of Hong Kong, Vol. XV, 29-33.

Hänni,H.A. (1992): ConsidÈrations terminologiques au sujet des Èmeraudes du NigÈria de couleur bleu-vert.- Revue de Gemmologie a.f.g. 113, 2-4.

Schmetzer,K., Hänni,H.A., Jegge,E.P. & Schupp, F.-J.(1992): Dyed natural Corundum as a Ruby Imitation.- Gems & Gemology, Summer, 112-115.

Hänni,H.A. (1992): Identification of fissure-treated gemstones.- J.Gemm. 23, 4, 201-205

Hänni,H.A. (1992): Erkennung von Edelsteinen mit behandelten Rissen.- Deutsche Goldschmiede Zeitung, 3, 206-210.

Hänni,H.A. (1992): Identification des fissures traitÈes.- Rev.Gemm.afg, 110, 10-12.

Hänni,H.A. (1992): Blue-green emerald from Nigeria: A question of terminology. Austral.Gemmol. 18, 1, 16-18.

Hänni,H.A. (1992): New fracture filling materials have replaced oil.- ICA Gazette,March, 4-5.

Hänni,H.A. & Schmetzer,K. (1991): New rubies from the Morogoro area, Tanzania.- Gems & Gemology, Fall, 156-167.

Hänni,H.A. (1991): Edelsteine der Korundgruppe.- SUGZ, 12, 29-36. D, F (Les gemmes du groupe des corindons)

Hänni,H.A. & Schmetzer,K. (1991): Rubine aus der Gegend von Morogoro in Tansania.- Deutsche Goldschmiede Zeitung, 11, 110-114.

Hänni,H.A. (1991): The case for blue-green emerald.- Jewellery News Asia.- July, 88+90.

Hänni,H.A. (1991): Gemmologie in China.- SUGZ , Monat ?, 29-31.

Hänni,H.A. (1991): Einige gemmologische Aspekte bei ostafrikanischen Korunden.- Deutsche Goldschmiede Zeitung, 4, 202-203.

Hänni,H.A. (1990): Esmeraldas: No es oro todo que reluce.- Arte y Joya, Nr.90, 43-47.

Hänni,H.A. (1990): Les gemmes du groupe des bÈryls.- Rev.Gemm.afg., 104, 8-12.

Hänni,H.A. (1990): Beitrag zu den Erkennungsmerkmalen der Kaschmir-Saphire.-Z.Dt.Gemmol.Ges. 39, 2/3, 107-120.

Hänni,H.A. (1990): A contribution to the distinguishing characteristics of sapphire from Kashmir.- J.Gemmol. 22, 67-75.

Hänni,H.A. (1990): Edelsteine der Beryll-Gruppe.- Lapis, 3, 11-15.

Hänni,H.A. (1990): Reliability of origin determinations for gemstones.- in "A question of origin" by R.W.Hughes, Gemological Digest, 3, 1, 28-32.

Hänni,H.A. (1989): What to look for in Vasar synthetic emerald.- Jewellery News Asia, September, 178-179.

Hänni,H.A. (1989): Les Feldspaths.- Revue de gemmologie a.f.g. , No. 101, 19-20.

Hänni,H.A. (1989): Iridescent natural glass from Mexico.- J.Gemmol., 21, 8, 488-495.

Hänni,H.A. (1989): Irisierendes natürliches Glas aus Mexico.- Z.Dt.Gemmol.Ges. 38, 2/3, 51-62.

Hänni,H.A. & Weibel,M. (1989): Ursache des Katzenaugen-Effektes bei erhitzten Zirkonen aus Sri Lanka.- Z.Dt.Gemmol.Ges. 38, 2/3, 95-101.

Hänni, H.A. (1989): Edelsteine der Beryll-Gruppe.- D: SUGZ, 10, 51-55. F: SUGZ, 11

Hänni, H.A., Düggelin,M. & Guggenheim,R. (1989): REM- und EDS-Untersuchungen in der Edelsteinprüfung. Echt - synthetisch - behandelt? Poster an der Tagung der Gesellschaft für Elektronen-Mikroskopie in Salzburg (Oktober).

Hänni, H.A. (1989): Zirkon ist nicht Zirkonia ! - Schweizer Uhren und Schmuck Journal, 1, 168. D,F,E,Sp.

Hänni, H.A. (1988): Certitude de la dÈtermination de l'origine des gemmes. - Revue de gemmologie a.f.g., No.97, 4-5.

Waber, N., Frieden.T., Hänni,H.A., Iff,R., Niggli,E. (1988): Zur Farbveränderung von Korunden bei Hitzebehandlung.- Z.Dt.Gemmol.Ges. 37, 1/2, 57-68.

Schwarz, D., Hänni,H.A., Martins,F.L. & Fischer M. (1988): The Emeralds of Fazenda Boa Esperanca (Taua,Ceara),Brazil: Occurrence and properties.- J.Gemmol. 21, 3, 168 - 178.

Hänni,H.A. & Weibel,M. (1988): Origin of the Cat's Eye-Effect in Heat-treated Zircons from Sri Lanka.- Australian Gemmologist. 16, 10, 363 - 366.

Hänni,H.A. (1988): An oil well in your garden ? .-Swiss Jewellery Journal (SUGZ), Nr.3, 461-464 (D,F,E,S).

Hänni,H.A. (1987): Garnets – A colourful Gemstone Family.- Swiss Watch & Jewelry Journal, 5, 691 - 694

Hänni,H.A. (1987): Grenats - Une famille de gemmes multicolores. Journal Suisse d'horlogerie et de bijouterie.- 5, 691- 694.

Hänni, H.A. (1987): Granate – eine farbenfrohe Edelstein-Familie. - SUGZ, 9, 28-32

Hänni, H.A., Schwarz,D. & Fischer,M. (1987): The emeralds of the Belmont-Mine, Minas Gerais, Brazil.- J.Gemm. 20, 446-456.

Hänni, H.A., Schwarz,D. & Fischer,M. (1987): Die Smaragde der Belmont-Mine, Minas Gerais, Brasilien: Vorkommen und Charakteristika. - Z.Dt.Gemmol.Ges. 36, 33-49.

Hänni, H.A. (1987): On corundums from Umba valley, Tanzania.- J.Gemmol., 20,5, 278-284.

Hänni, H.A. & Bosshart,G. (1987): Damage to cut Diamonds.- J.Gemmol., 20, 6, 339-343.

Hänni, H.A. & Bosshart,G. (1987): Schäden an geschliffenen Diamanten. - Schweiz. Uhren & Schmuck Journal, 2, 383-386, (E,F,S)

Hänni, H.A. (1986): Behandelte Korunde mit glasartigen Füllungen. - Z.Dt.Gemmol.Ges. 35, 87-96. (F,E,S)

Hänni, H.A. (1986): Korunde aus dem Umba-Tal, Tansania.- Z. Dt. Gemmol. Ges., 1/2, 1-13.

Hänni, H.A. (1986): Glasartige Füllungen in Rubinen und Saphiren.- Schweiz. Uhren und Schmuck Journal, 5, .

Hänni, H.A. (1984): Testing the authenticity of corundum - Methods and limitations.- Swiss Watch & Jewelry Journal, 6, 23-30, (D,F,S).

Hänni, H.A. (1983): Weitere Untersuchungen an einigen farbwechselnden Edelsteinen.- Z.Dt.Gemmol.Ges. 32, 99-106.

Hänni, H.A., Kerez,C.J. (1983): Neues vom Smaragd-Vorkommen von Sta. Terezinha de Goi·s, Brasilien. Z.Dt.Gemmol.Ges. 32, 50-58.

Hänni, H.A. (1983): The influence of the internal structure of pearls on Lauegrams.- J.Gemmol. XVIII, 386-400.

Schmetzer, K., Bosshart,G. & Hänni, H.A. (1982): Naturfarbene und behandelte gelbe und orange-braune Saphire. - Z.Dt.Gemmol.Ges. 31, 265-280.

Hänni, H.A., Stern,W.B. (1982): ¤ber die Bedeutung des Gallium-Nachweises in Korunden.- Z.Dt.Gemmol.Ges. 31, 255-260.

Stern, W.B., Hänni,H.A. (1982): Energy-dispersive X-ray spectrometry: a non-destructive tool in gemmology.- J.Gemmol. XVIII, 285-296.

Hänni,H.A. (1982): Perlendiagnose mit Laue-Aufnahmen. - Z.Dt.Gemmol.Ges. 31, 131-142.

Bosshart,G., Frank,E., Hänni,H.A. & Barot,N. (1982): Blue colour-changing Kyanite from East Africa. J.Gemmol. XVIII, 205-212.

Hänni,H.A., Gunawardene, M. (1982): Untersuchungen an Titanit, einem für Sri Lanka neuen Edelstein.- Z.Dt.Gemmol.Ges. 31, 65-70.

Hänni,H.A. (1982): Zur Erkennung diffusionsbehandelter Korunde.- Z.Dt.Gemmol.Ges. 31, 49-57.

Hänni,H.A. (1982): Merkmale von erhitzten und diffusionsbehandelten Korunden.-SUGZ, 5, (D,F)

Hänni,H.A., Klein,H.H. (1982): Ein Smaragdvorkommen in Madagaskar.-Z. Dt. Gemmol. Ges. 31, 71-77.

Hänni,H.A. (1982): A contribution to the separability of natural and synthetic emeralds.- J.Gemmol. XVIII, 138-144.

Hänni,H.A., Gunawardene,M. (1982): Ferroaxinite - another new gem from Sri Lanka.-J.Gemmol. XVIII, 20-27.

Hänni,H.A. (1981): Chemischer Vergleich zwischen natürlichen und synthetischen Smaragden.- Z.Dt.Gemmol.Ges. 30, 214-218.

Hänni,H.A. (1981): Energiedispersive Rˆntgenfluoreszenz-Analyse in der gemmologischen Diagnostik.- Z.Dt.Gemmol.Ges. 30, 207-209.

Hänni,H.A., Frank,E. & Bosshart,G. (1981): Golden yelllow tourmaline of gem quality from Kenya.- J.Gemmol. XVII, 437-442.

Gunawardene,M., Hänni,H.A. (1981): First occurence of gem Sphene in Sri Lanka.- J.Gemmol. XVII, 381-385.

Hänni,H.A. (1980): Mineralogische und mineralchemische Untersuchungen an Beryll aus alpinen Zerrklüften.- Dissertation. Universität Basel.

Graeser,S., Schwander,H. & Hänni,H. (1979): Vigezzite, (Ca,Ce)(Nb,Ta,Ti)2O6, a new Aeschynite-type mineral from the Alps.- Min.Mag. 43, 459-462.

Hänni,H.A. (1979): Bazzit aus Kärnten, Oesterreich.- Ann. Naturhistor.Museum Wien, 82, 189-191.

Abrecht,J., Hänni,H. (1979): Eine Beryll-Phenakit(Be2SiO4)-Paragenese aus dem Rotondo-Granit.- SMPM 59, 1-4.

Hänni,H.A., Stern,W.B. & Glor,M. (1978): New Data on Stranskiite from Tsumeb, SouthwestAfrica.- Am. Mineral. 63,213-215.

Graeser,S., Hänni,H. (1976): Ein neuer Bazzit-Fund in den Alpen.- Urner Mineralienfreund,3,14,48-51.

Hänni,H.A., Schaffner,A. (1975): Edelsteinkunde.- Gewerbeschule Basel. Lehrmittel für Goldschmiede.