Resources & Links
Magnetism in Gemstones
Anderson, B.W. (1953). "Experiments with a Pocket Magnet", Journal of Gemmology, Vol. 4. No 4., p. 169-175
Dietrich, R. (1985), "Magnetic Properties", pp. 156-159, The Tourmaline Group, Van Norstrand Reinhold Company, Inc.
Feral, Kirk (2012) “Detecting HPHT Synthetic Diamond Using a Handheld Magnet”. Gems & Gemology Vol.48, No.4, pp. 262-272.
Feral, Kirk (2017) "A Man, a Magnet, and an Idea", Gemmology Today magazine, August 2017 issue, pp. 64-67.
Feral, Kirk (2019) "Masters of Green: Chromium and Vanadium Part I" and " Masters of Green: Chromium and Vanadium Part 2", Gemmology Today magazine, March 2019, pp. 28-32 and June 2019, pp. 38-45.
Feral, Kirk (2022) "Chromium-bearing Translucent Green Common Opal", Journal of Gemmology, Vol. 38 No. 2, pp. 120-122.
Gumpesberger, Sylvia (2006) “Magnetic Separation of Gemstones”. Canadian Gemmologist. Vol. 27 No.4, pp.120-124
Hanneman, W.W. (2002) "The Magnetic Index". The Australian Gemmologist. Vol. 21 No.6, pp.234-235
Hoover, D.B and Williams, Bear (2007) "Magnetic Susceptibility for Gemstone Discrimination".The Australian Gemmologist Vol. 23, pp.146-159
Hoover, D.B., Williams, B., Williams, C. and Mitchell, C. (2008) "Magnetic Susceptibility, a Better Approach to Defining Garnets". Journal of Gemmology Vol. 31 No. 3/4, pp. 91-103
Hoover, D.B. (2011) "Determining Garnet Composition from Magnetic Susceptibility and Other Properties". Gems & Gemology, Vol. 47 No.4, pp. 272-285
Koivula J. I. and Fryer C.W. (1984) "Identifying Synthetic Gem-Quality Diamonds: An Update". Gems and Gemology Vol 20, No. 3, pp.146-158
Matlins A., Bonanno A.C (2008) Gem Identification Made Easy, 4th ed., GemStone Press, Woodstock, VT. Chapter title “The Synthetic Diamond Detectors”, p233-236
Pradat, Thierry & Gauthier, Jean-Pierre (2011) "A Visual Test of the Magnetic Attraction of Gem Materials". Revue de Gemmologie AFG 175 p. 14-18. (To view the paper translated into English, click here: Google Translate. This is the most recent published paper about testing gemstones with a hand-held magnet).
Rossman, George and Kirshvink, J.L. (1984) "Magnetic Properties of Gem-Quality Synthetic Diamonds". Gems and Gemology Vol. 20, No.3 pp. 163-166
Sigamony, A. (1944) "The Magnetic Properties of Tourmaline and Epidote". Indian Academy of Science Proceedings 20(A) p. 200-203
Magnetism, Gem Color and Spectroscopy References
Magnets can be purchased at kjmagnetics.com
A useful chart that includes information on the magnetism of the elements including metals such as gold and silver is the Magnetic Susceptibilities of the Elements and Inorganic Compounds published in CRC Handbook of Chemistry and Physics, 98th
Edition, 2017, John R. Rumble, ed., CRC Press/Taylor & Francis, Boca Raton, FL.
GTPro (Gemology Tools Professional) is a software program for gem identification that incorporates magnetic responses from the Magnetic Susceptibility Index for Gemstones.
Handbook of Gemmology is an 860 page online reference book that now contains information on magnetic testing of gemstones.
The Causes of Color, a 1980 Scientific American article by Dr. Kurt Nassau.
Fritsch, E. and Rossman, G. (1987), "An Update on Color in Gems", Gems & Gemology Vol. 23 No. 3, pp. 126-139
Anderson, Basil and Payne, James (2010) The Spectroscope and Gemmology, 2nd Edition, Gemstone Press, Woodstock, VT.
The Colors of Minerals and the Spectroscopy Database for Minerals CalTech web pages by Dr. George Rossman.
A Student's Guide to Spectroscopy by Colin Winter (2003) can be purchased from OPLspectra.com
John Harris' gem spectroscopy website gemlab.co.uk.
Information about Diamond can be found at The Consumer's Guide to Buying Diamonds at Beyond4c's.com
Abduryim, A et al. (2006), "Paraiba-type Copper-bearing Tourmaline from Brazil, Nigeria and Mozambique: Chemical Fingerprinting by LA-ICP-MS", Gems & Gemology, Vol. 42 No.1, pp. 4-21
Dietrich, R. (1985), "Magnetic Properties", pp. 156-159, The Tourmaline Group, Van Norstrand Reinhold Company, Inc.
Halvorsen, A., Jensen, B.B. (1997), "A New Colour-change Effect", Journal of Gemmology, Vol. 25 No. 5, pp.325-330
Henry, D.J. et al. (2011), "Nomenclature of the Tourmaline Super-group Minerals", American Mineralogist, Vol. 96, pp. 895-913
Laurs, B. et al. (2008) "Copper Bearing (Paraiba-type) Tourmaline from Mozambique", Gems & Gemology, Vol. 44 No. 1, pp. 4-30
Laurs, B. et al. (2011), "Yellow Mn-Rich Tourmaline from the Canary Mining Area Zambia", Gems & Gemology, Vo. 43, No. 4, pp. 314-331
Liu, Yan & Fry, B.A. (2006) "A colorimetric study of tourmaline from Mozambique which shows a reverse alexandrite effect", Journal of Gemmology, Vol. 30, No. 3/4, pp. 201-206
Merkel, P. & Breeding, C. (2009), "Spectral Differentiation Between Copper and Iron Colorants in Gem Tourmalines", Gems & Gemology, Vol. 45 No. 2, pp. 112-119
Nassau, Kurt (1975), "Gamma Ray Induced Changes in the Color of Tourmalines", American Mineralogist, Vol. 60, pp. 710-713
Okrusch, M. et al., (2016), "Major and Trace Element Composition of Paraiba-type Tourmaline from Brazil, Mozambique and Nigeria", Journal of Gemmology, Vol. 35/ No.2, pp. 120-139.
Reinitz, I. and Rossman, G. (1988), "The Role of Natural Radiation in Tourmaline Coloration", American Mineralogist Vol. 74, pp. 822-825
Sigamony, A. (1944) "The Magnetic Properties of Tourmaline and Epidote". Indian Academy of Science Proceedings 20(A) p. 200-203
Garnet References
Deer W. A., Howie R.A., Zussman J., Rock-forming Minerals Volume 1A: Orthosilicates, 2nd edition, Halsted Press, New York, Garnet Group pp. 468-698
Gaft, M. et al. (2013) Laser-induced time resolved luminescence of natural grossular Ca3Al2(SiO4)3. Journal of Luminescence Vol. 137, pp. 43-53
Gaustoni, A; Pezzota, F; Superchi, M; Demartin, F; (2001) "Pyrope from the Dora Maira Massif, Italy". Gems & Gemology, Vol. 37 (No. 3) pp. 198-204
Garnet: Great Balls of Fire (2008) extraLapis No. 9, Lithographie, LLC
"Garnet" The Gemology Project GemologyOnline.com (Garnet classification)
Geiger, Charles A. (2018) “Heat capacity and entropy behavior of andradite: A multi-sample-and methodological investigation”. European Journal of Mineralogy, Vol. 30 pp. 681-694
Grande, L. and Augustyn, A. (2009) "Garnet Group" pp.170-194, Gems and Gemstones, University of Chicago Press.
Hainschwang, T. and Notari, F. (2006) "The Cause of Iridescence in Rainbow Andradite from Nara, Japan". Gems & Gemology Vol 42 (No. 4) p. 248-258
Jackson, Brian (2006) “The Garnets” pp. 195-237, Gems 6th edn. Elsevier LTd., edited by Michael O’Donoghue.
Johnson, M. (1995) "Gem-Quality Grossular-Andradite: A New Garnet from Mali". Gems & Gemology Vol. 31, No.3, pp. 152-166
Newman, Renee (2011) Exotic Gems Volume 2, International Jewelry Publications, Los Angeles, CA. Chapter title "The Garnet Group", pp. 95-145
Seifert, A. & Vrana, S. (2005) "Bohemian Garnet". Czech Geological Survey Vol. 80 No.2, pp. 113-124
Schmetzer, K., Hainschwang, T., Kiefert, L., & Bernhardt, H. (2001) "Pink to Pinkish Orange Malaya Garnets from Bekily, Madagascar". Gems & Gemology Vol. 37, No.4, pp. 296-308
Schmetzer, K., Hainschwang, T., Bernhardt, H. & Kiefert, L. (2002) "New Chromium-and-Vanadium-Bearing Garnets from Tranoroa, Madagascar". Gems and Gemology Vol. 38, No 2., p 148-155
Schmetzer, K., Bernhardt, H., Bosshart, G., Hainschwang, T. (2009) "Colour-Change Garnets from Madagascar: Variation of Chemical, Spectroscopic and Colorimetric Properties". Journal of Gemmology Vol. 31, No. 5-8, pp. 235-282
Stockton, C. & Manson, D. (1988) "A Proposed New Classification for Gem-Quality Garnets". Gems & Gemology Vol. 21 No. 4, pp. 205-218
Stockton, C. (1988) "Pastel Pyropes". Gems & Gemology Vol. 24 No. 2, pp. 104-106
Sun, Ziyin, et al. (2015) "Vanadium and Chromium Bearing Pink Pyrope Garnet: Characterization and Quantitative Colorimetric Analysis", Gems and Gemology, Vol. 51 No. 4, pp. 348-369.
Sun, Ziyin and Renfro, Nathan (2107) "Raspberry-red garnet with black core", Gems and Gemology, Vol. 53 No. 2, pp. 250-252.
Winchell, H. (1958) "The Composition and Physical Properties of Garnet". The American Mineralogist Vol. 43 (May-June) pp. 595-600
Zhu, M & Guo, Y. (2023), “New Insights into the Coloration Mechanism in Spessartines and the Impact of Munsell Neutral Grey Backgrounds”, Crystals, Vol. 13, pp. 1-12
Synthetic Garnet References
Kennedy, Lisa (2023), “Luminescent Synthetic Garnet-like Crystals”, Gems & Gemology, Vol. 59 No. 1, pp. 125-127
Kinsman, K. and McKittrick, J. (1994), “Phase Development and Luminescence in Chromium-Doped Yttrium Aluminum Garnet (YAC:Cr) Phosphors”, Journal of the American Ceramics Society, Vol. 77 No. 11, pp. 2866-2872
Kruczek, M et al. (2009), “Electronic Structure of Y3Al5O12:V Single Crystals, Comparison with Sintered Ceramics”, Proceedings of the European Conference “Physics of Magnetism”, Vol. 115 No.1, pp 209-212
Olvera, O. et al. (2019), “Effect of the Trivalent Erbium Concentration on the Luminescent Properties of TiO2 Er3+ Composites”, Computacion y Systemas, Vol. 23 No. 1, pp. 89-94
Sysiak, A. et al. (2020), “Transparent Cobalt-doped Yttrium Aluminum Garnet (Co2+:YAG) Ceramics—An Innovatory Fast Saturable Absorber”, Journal of the American Ceramic Society, Vol. 104, pp. 1204-1209
Tang, F. et al. (2014), “Dependence of Optical and Thermal Properties on Concentration and Temperature for Yb:YAG Laser Ceramics”, Journal of Alloys and Compounds, Vol. 593, pp. 123-127
Trento, Chin (2023), “An Introduction to 7 Types of Synthetic Garnet Materials” Stanford Advanced Materials, samaterials.com
Yu, Y. et al. (2000), “Concentration Effects of Er3+ ion in YAG:Er Laser Crystals”, Journal of Alloys and Compounds, Vol. 301, No. 1-2, pp. 204-208
Zhang, Li et al. (1999), “Single-crystal Hydrostatic Compression of Synthetic Pyrope, Almandine, Spessartine, Grossular and Andradite Garnets at High Pressures”, Physics and Chemistry of Minerals, Vol. 27 No. 1, pp. 52-58
Sapphire and Ruby References
Dubinsky, E., Stone-Sundberg, J., Emmet, J. (2020) "A Quantitative Description of the Causes of Color in Corundum", Gems & Gemology, Vol. 56 No. 1, pp. 2-28
Emmett, John L., (2003) "Beryllium Diffusion of Ruby and Sapphire", Gems & Gemology, Vol. 39 No. 2, pp. 84-135.
Emmett, J., Dubinsky, E. Hughes, R. (2017) " Ruby and Sapphire: A Gemologist's Guide to Understanding Color.", Sinkankas Symposium Program, Fourteenth Annual Sinkankas Sympoisium: Sapphire.
Emmet, J. et al., (2017), "The Role of Silicon in the Color of Gem Corundum", Gems and Gemology, Vol. 53 No. 1, pp. 42-47.
Hanni, A., Schmetner, K. & Heinz-Jurgen, B. (1994), "Synthetic Rubies by Duoros: A New Challenge or Gemologists"., Gems & Gemology, Vo. 30, No.2, pp. 72-86.
Makoto, M.; Katsurada, Y.; Saruwatari, K. (2018), "Update on Trace-Element Chemical Characteristics of Golden Sheen Sapphire"., Gems & Gemology, Vol. 54 No. 2, pp. 238-241.
Nassau, Kurt, (1981) "Heat Treating Ruby and Sapphire: Technical Aspects", Gems & Gemology, Vol. 17, No. 3, pp. 121-131.
Shah Raabell, (2012), "The Analysis of Natural Gemstones and their Synthetic Counterparts using Analytical Spectroscopy Methods". Edinburgh Napier University.
Smith, Christopher P., (2010) "Inside Sapphires", Rapaport Diamond Report, Vol. 3. No. 7
Thomas, V. et al., (1997), "Tairus Hydrothermal Synthetic Sapphires Doped with Nickel and Chromium", Gems and Gemology, Vol. 33, No. 3, pp. 188-202.
Treatments and info about untreated Sapphires at wildfihgsems.com
Vigier, M. and Fritsch, E. (2023) “More on orange Luminescence in Corundum”, Gems & Gemology, Vol. 58, No. 3, PP. 376-377
Spinel References
Chauvire, Boris et al., (2015) “Blue Spinel from the Luc Yen District of Viet Nam”, Gems & Gemology, Vol. 51 No. 1, pp. 2-17
D’Ippolito, Veronica et al., (2015) “Color Mechanisms in Spinel: Cobalt and Iron Inertplay for the Blue Color”, Physics and Chemistry of Minerals, Vol. 42, pp. 431-439
Liu Yicen et al. (2023). “Color Mechanism and Spectroscopic Thermal Variation of Pink Spinel Reportedly from Kuh-I-Lal, Tajikistan”, Gems & Gemology, Vol. 58, No. 3, pp. 338-353
Muhlmeister, S. et al, (1993), “Flux-Grown Synthetic Blue and Red Spinels From Russia", Gems and Gemology, Vol.29, No. 2, pp. 81-98
Peretti, A., Gunther, D. and Haris, M. , (2015), “New type of treatment of spinel discovered involving heat-treatment and cobalt-diffusion", Gem Research Swiss Lab, May 22 GRS Alert @ www.gemresearch.ch
Saeseaw, S. et al., (2009), “Distinguishing Heated Spinels from Unheated Natural Spinels and from Synthetic Spinels”, GIA Laboratories Bangkok & New York
Shigley, James E. and Stockton, Carol M., (1984) “Cobalt Blue Gem Spinels”, Gems & Gemology, Notes and Techniques, Vol. 20, No. 1, pp. 34-41
“Spinel” @ gemologyproject.com
Zhao, L. et. al., (2022), "Gemological and Spectroscopic Characteristics of “Jedi” Spinel from Man Sin, Myanmar", 12 (11): 1359, pp. 1-13
Fluorescence References
Fosbury, Robert (2013) “Fluorescence Spectroscopy of Minerals: 1- Using a Spectrometer”, Journal. Pp.5-17.
"Fluorescent Minerals", https://www.uvminerals.org/, The Fluorescent Mineral Society.
Gotze, Jens “Detection of Defects in Minerals by Luminescence Spectroscopy” PowerPoint presentation.
Online Database of Luminescent Minerals, Gerard Barmarin, 2009-2010.
Schneider, Stuart (2006) The World of Fluorescent Minerals, Schiffer Publishing Ltd.
Robbins, Manuel, (1994) Fluorescence: Gems and Minerals Under Ultraviolet Light, Geoscience Press.
Vigier, M. and Frtisch, E. (2020) "Pink Axinite from Merelani, Tanzania: Origin of Colour and Luminescence", Journal of Gemmology, Vol. 37 No. 2, pp. 192-205.
Axinite References
Andreozzi, G. et al. (2000), “Crystal Chemistry of the Axinite-group Minerals: A Multi-analytical Approach”, American Mineralogist, Vol.85, pp. 698-706
Andreozzi, G. et al. (2004), “Site Distribution of Fe2+ and Fe3+ in the Axinite Mineral Group: New Crystal-chemical Formula”, American Mineralogist, Vol. 89, pp. 1763-1771
Arlabosse, J. et al., (2008), “A Blue Manganaxinite”, Gems & Gemology, Vol. 44 No. 1, p. 81
Chalmin. E. et al., (2008) “A Pre-Edge Analysis of Mn K-edge XANES Spectra to determine Speciation of Manganese in Minerals and Glasses”, Contributions to Mineralogy and Petrology, Vol. 157, No. 1, pp. 111-126
Clark, B. (2016), "Axinite from Shigar Fort, Northern Pakistan", Journal of Gemmology, Vol. 35 No. 2, pp 96-97
Deer W. A., Howie R.A., Zussman J., (1962) Rock-forming Minerals Volume 1A: Orthosilicates, 2nd edition, Halsted Press, New York, Garnet Group pp. 590-602
Feral, Kirk (2019) "Masters of Green: Chromium and Vanadium Part 2", Gemmology Today magazine, June 2019, pp. 38-45.
Filip, J. et al. (2008), “Low-temperature Calorimetric and Magnetic Data for Natural End-members of the Axinite Group”, American Mineralogist, Vol. 93 pp. 548-557
Fritz, E. & McClure, S. (2007), “Color-zoned Axinite from Pakistan”, Gems & Gemology, Vol. 43 No. 3, pp. 254-255
Grew, E., (2018) “Tinzenite, a member of the axinite group with formula revised to Ca2Mn2+ 4 Al4[B2Si8O30](OH)”, European Journal of Mineralogy, Vol. 30, pp. 177-182
Haberman, D. et al., (1997), “Low Limit of Mn2+ -activated Cathodoluminescence of Calcite: State of the Art”, Sedimentary Geology, Vol. 116, pp. 13-24
Jang-Green, H. et al., (2007), “Two Axinite Species from Tanzania”, Gems & Gemology, Vol. 43 No. 4, pp. 373-375
Jobbins, E. et al. (1975), “Magnesioaxinite, A New Mineral Found as a Blue Gemstone from Tanzania”, Journal of Gemmology Vol. 14 No. 8, pp. 368-375
Lauf, R. (2007), Collector’s Guide to the Axinite Group, Schiffer Pub. Ltd., Atglen, Pennsylvania, 93 pp.
Laurs, B. & Renfro, N., (2016), “‘Black’ Axinite”, Journal of Gemmology, Vol. 35 No. 4, pp 277-278
Lumpkin, G. & Ribbe., (1979) “Chemistry and Physical properties of Axinites”, American Mineralogist, Vol. 64, pp. 635-645
Matsubara, S, et al. (2011), “Axinite-(Mg) from Kashio, Nagano Prefecture, Japan”, Bulletin of the National Museum of Natural Sciences, Series C No. 37, pp. 1-4
Milton, C. et al. (1953) “The Identity of Tinzenite with Manganoan Axinite”, American Mineralogist, Vol. 38, pp. 1148-1158
Pay, D., (2017), “Magnesio-Axinite from Merelani, Tanzania”, Gems & Gemology, Vol. 53, No. 1, pp. 128-130
Pearson, B. (2006) “The Control of Cathodoluminescence in Dolomite by Iron and Manganese”, Sedimentology, Vol. 28. No. 5, pp. 601-610
Pringle, I. & Kawachi, Y., (1980), “Axinite Mineral Group in Low-grade Regionally Metamorphosed Rocks in Southern New Zealand”, American Mineralogist, Vol. 65, pp. 119-1129
Quinn, E. & Breeding, C. (2005), “Yellowish Orange Magnesioaxinite”, Gems & Gemology, Vol. 41, No. 2, pp. 170-171
Reinitz, I. and Rossman, G. (1988), "The Role of Natural Radiation in Tourmaline Coloration", American Mineralogist Vol. 74, pp. 822-825
Rossman, G. & Mattson, S., (1986) “Yellow, Mn-rich Elbaite with Mn-Ti Intervalence Charge Transfer”, American Mineralogist, Vol. 71, pp. 599-602
Sugitani, Y. et al. (1974), “Optical Absorption Spectra of Iron (III) and Chromium (III) Doped in Synthetic Yttrium-Aluminium-Garnets (YAG)”, Mineralogical Journal, Vol. 7, No. 5, pp. 445-455
Vigier, M. & Fritsch, E., (2020), “Pink Axinite from Merelani, Tanzania: Origin of Colour and Luminescence”, Journal of Gemmology, Vol. 37 No. 2, pp. 192-205
Williams, B. & C., Laurs, B., (2014), “Colour-change Axinite-(Mn) from Tanzania", Journal of Gemmology, Vol. 34 No. 3, pp.191–192
Zagorsky, V. et al. (2015), “Axinite-(Mn) from Miarolitic Granitic Pegmatites of the Malkhan Gem-tourmaline Deposit (Transbaikalia, Russia): Composition, Paragenesis and Conditions of Formation”, European Journal of Mineralogy, Vol. 28, pp. 811-824
Zhu, M & Guo, Y. (2023), “New Insights into the Coloration Mechanism in Spessartines and the Impact of Munsell Neutral Grey Backgrounds”, Crystals, Vol. 13, pp. 1-12
Zwaan, J.C, et al., (2018), “Axinite-Mg from Parachinar, Pakistan”, Journal of Gemmology, Vol. 36 No. 4, pp 281-283
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Magnetism in Gemstones
An Effective Tool and Method for Gem Identification
© Kirk Feral
