Contact: Tina Hilding, communications coordinator, College of Engineering and Architecture, 509/335-5095, thilding@wsu.edu
Researchers Determine Star Material of Idaho State Gem
Researchers from the Washington State University School of
Mechanical and Materials Engineering have for the first time
determined the cause of the 'star' in Idaho's famous star garnet,
the official state gem of the Gem State. Idaho is one of only three
places in the world that are known to have star garnets.
While simple curiosity was the initial instigator for the research,
the work promises to be of interest, particularly in high
technology industries, says Grant Norton, professor in the WSU
School of Mechanical and Materials Engineering and associate dean
of Research and Graduate Programs for the College of Engineering
and Architecture. Crystals with the garnet structure are used in
solid-state lasers and are being studied for use in radiation
detectors.
Norton and a colleague first wondered about the stars' origins
after walking into Gem State Jewelers in Moscow, Idaho a few years
ago. While there was suspicion of their origin, nobody really knew
what caused them.
Using donated garnets from the jewelers, Norton and Maxime Guinel,
a graduate student in materials science, used transmission electron
microscopy to determine conclusively for the first time that the
star is caused by inclusions of rutile, a mineral composed of
titanium oxide, in the garnet. The star can either contain six rays
or four, based on the orientation of the tiny needles of rutile.
They also determined the microstructural characteristics that
affect the quality of the 'star'.
Their results were published today (Feb. 15) in the Journal of
Materials Science.