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  • 10 Practical Uses
  • Overview
    • Overview pg 2- Diamagnetic (non-magnetic) Gems
    • Overview pg 3- Factors that Affect Magnetism
    • Overview pg 4- The Magnetic Metals that Color Gems
    • Overview pg 5- Spectroscopy in Relation to Magnetism
    • Overview pg 6- Fluorescene in Relation to Magnetism
    • Overview pg 7- Quantitative Measurements of Magnetism
  • How To Use a Magnet
    • How To pg 2- Floatation Method and Direct Method
    • How To pg 3- Factors That Affect Magnetic Responses
    • How To pg 4- Translucent and Opaque Gems that Pick Up
    • How To pg 5- Separating Look-alike Gems
    • How To pg 6- Magnetic Separation Chart for Look-alike Gems
  • Diamond
  • Sapphire & Ruby
    • Sapphire & Ruby pg 2- Ruby
  • Spinel
    • Spinel pg 2- Red Spinel, Pink Spinel & Other Colors
    • Spinel pg 3- Synthetic Spinel
  • Tourmaline
    • Tourmaline pg 2- Black, Orange, Blue, Green Tourmalines
    • Tourmalines pg 3- Pink, Red, Yellow and Other Colors
    • Tourmalines pg 4- Paraiba Tourmalines
  • Garnet
    • Garnet pg 2- Understanding Garnets through Magnetism
    • Garnet pg 3- How Magnetic Are Garnets?
    • Garnet pg 4- A Rainbow of Color in Garnets
    • Garnet pg 5- A Graph of All Gem Garnets
      • 1958 Winchell Diagram
    • Garnet pg 6- Pyralspite Garnets: Almandine, Pyrope & Spessartine
    • Garnet pg 7- Color Change Garnet
    • Garnet pg 8- Malaya Garnet
    • Garnet pg 9- Pastel Pyrope: A New Variety
    • Garnet pg 10- Rhodolite & Chrome Pyrope
    • Garnet pg 11- Ugrandite Garnets: Andradite & Uvarovite
    • Garnet pg 12- Ugrandite Garnets: Grossular Garnet
    • Garnet pg 13- Distinguishing Between Garnet Species and Varieites
    • Garnet pg 14- Gem Garnet Classification System
  • Resources & Links
  • Comments Blog
  • About Us
  • The Magnetic Index
    • Magnetic Index pg. 2- About the Magnetic Susceptibility Index
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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 online magazine, August 2017 issue, pp. 64-67.


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 31 (3/4) p. 91-103


Hoover, D.B. (2011) "Determining Garnet Composition from Magnetic Susceptibility and Other Properties". Gems & Gemology 47(4) p. 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


Tourmaline References


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  



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



Fluorescence References


Fosbury, Robert (2013) “Fluorescence Spectroscopy of Minerals: 1- Using a Spectrometer”, Journal. Pp.5-17.


"Fluroescent 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.




                                                    ___________________               

                            Magnetism in Gemstones 

                                   An Effective Tool and Method for Gem Identification  

                                                                                   © Kirk Feral

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