Semi-Precious Gemstones: Kunzite
Kunzite (Spodumene) used in Jewelry
Source: Afghanistan, Brazil, Madagascar, Myanmar, Pakistan, USA
Kunzite is a pale-pink to lilac colored gemstone variety of the mineral spodumene, that is a pyroxene mineral consisting of lithium aluminium inosilicate. Kunzite was named after George F. Kunz who was a buyer for Tiffany & Co, and a noted American mineralogist who first identified the pink variety of spodumene in 1902.
Spodumene (lithium aluminium silicate) naturally occurs in colorless form as well as in yellowish-brown or greenish-yellow which is called "hiddenite," and in purple, pink or lilac which is called "Kunzite." Spodumene, which occurs in lithium rich granites and pegmatites, is also a source of lithium. The main chromophore in Kunzite is manganese which gives the stone its characteristic pink color. The primary source for Kunzite is in Minas Gerais, Brazil, with secondary sources in Afghanistan and Madagascar. It is also found in Canada, Mexico, and the United States.
Striated rough Kunzite |
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Faceted Kunzite (photo: Dan Dennis) |
Kunzite presents challenge to the lapidary, as the top and bottom of the crystal exhibit the deepest colors, and orientation is critical to ensure that the light passing through the gem enhances the desired color. Additionally, since Kunzite is strongly pleochroic, there can be a significant variation in color intensity when the cut stone is viewed from different directions. Kunzite can also have growth-tube inclusions or fractures that need to be avoided when cutting.
Due to the effect of photochromism, some specimens of Kunzite may be susceptible to fading when exposed to strong sunlight. Off-color stones can be heated to improve color, typically by heating to the stone to around 300 degrees F (150 C).
Kunzite (Spodumene) Crystallography, Chemistry, Physical Properties
Kunzite (Spodumene) Optical Properties
In 1996, a significant 47-carat specimen of Kunzite was sold for over $ 400,000 by Sotheby's, the stone belonging to the Estate of Jacqueline Kennedy Onassis. The Kunzite ring was purchased by the late President John F. Kennedy as a gift to Jacqueline, but was never given due to his assassination.
Bibliography and Reference on Kunzite
1. Paul R. Shaffer, Rocks, Gems and Minerals  . Martin's Press
2. Renee Newman, Gemstone Buying Guide . International Jewelry Publications; 2nd edition
3. Antoinette L . Matlins, Antonio C. Bonanno, Gem Identification Made Easy . Gemstone Press
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