The May Gem News from Pala International reports that:
Hackmanite is a phenomenal variety of sodalite and a member of the feldspathoid group, hackmanite is mostly found in a translucent cabochon form. This month we feature a transparent faceted hackmanite from Afghanistan. This gem is near-flawless and exhibits all the unusual optical characteristics associated with hackmanite.
Hackmanite is known for its unique color-shift phenomenon when subjected to warm white light or daylight. The phenomenon is known as tenebrescence. Hackmanite will often increase in saturation when allowed to be “charged up” in daylight and sometimes shifts between lavender and magenta hues. Long-wave ultraviolet light also brings out an amazing fluorescence, as seen directly below; in this case we see a glowing orange/yellow hue. The distinctive color phenomena are derived from the sulphur component in hackmanite’s chemistry. Light can polymerize the sulphur into different-leng
th molecules and ions that, in turn, have different colors. (Thanks to Dr. George R. Rossman for clarification of the color phenomena science. See this Caltech webpage for more on the sodalite group.)This stone is the May Featured Stone: Lavender hackmanite from Afghanistan, 7.87 carats, 16.28 x 11.08 x 8.64 mm. Inventory #17382. (Photo: Mia Dixon)
2 comments:
I recently saw beads of this material on ebay and decided to look it up online. I'm always on the lookout for unusual gemstone beads and the color change aspect really intrigued me. (I was having some difficulty understanding tenebrescence but the explanation of how the sulfur reacts to uv light and in turn causes the change in color made it easy for me to grasp. Thank you for that.) The color change is incredible and the gem you picture is of amazing quality--what I've seen thus far has been a bit cloudy and, well, unimpressive. I hope to see more of this gemstone available in the future, particularly in bead form, as that is what I design with. Thank you for sharing this information. --Tracy
Most of the Hackmanite that I saw in Tucson last year was milky also.
That is why when Pala International offered this gorgeous stone - I had to post it!
Good luck in your search...
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