Thomas Lameris Heather A. Lowers Colin MacRae Edward P. Vicenzi 2024 <p class="chapter-para">Cultures throughout history have valued jadeite jade (hereinafter jade), a natural material assemblage composed predominately of the NaAl endmember pyroxene, jadeite (NaAlSi₂O₆) that is prized for its mechanical properties and enticing coloration [<span id="jumplink-ozae044.009-B1" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B1" data-google-interstitial="false">1</a>,<span>&nbsp;</span><span id="jumplink-ozae044.009-B2" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B2" data-google-interstitial="false">2</a>]. The geological setting for the formation of jadeite-rich rocks and associated complex geochemical phenomena is well documented in the literature [<span id="jumplink-ozae044.009-B3 ozae044.009-B4 ozae044.009-B5" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B3 ozae044.009-B4 ozae044.009-B5" data-google-interstitial="false">3-5</a>]. Unlike single crystal gems, jade often contains a mixture of colors, but the stone is perhaps best known for exhibiting a range of green hues from pale green to blue green, and to deep green [<span id="jumplink-ozae044.009-B1" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B1" data-google-interstitial="false">1</a>,<span>&nbsp;</span><span id="jumplink-ozae044.009-B6" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B6" data-google-interstitial="false">6</a>]. Efforts to classify jade color include qualitative matching to a set of reference color tiles, and less commonly, use of a more quantitative set of color perception values first established by International Commission on Illumination’s (CIE 1931) color space, which includes values for light-dark luminance level (L*), a green-red vector (a*), and a blue-yellow vector (b*) [<span id="jumplink-ozae044.009-B7" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B7" data-google-interstitial="false">7</a>,<span>&nbsp;</span><span id="jumplink-ozae044.009-B8" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B8" data-google-interstitial="false">8</a>]. Two principal mechanisms have been identified as the cause of green coloration in jadeite: 1) the chemical state of impurity Fe, either 2+ or 3+, and 2) minor to trace Cr in the crystal structure [<span id="jumplink-ozae044.009-B9" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B9" data-google-interstitial="false">9</a>,<span>&nbsp;</span><span id="jumplink-ozae044.009-B10" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B10" data-google-interstitial="false">10</a>]. Previous studies have associated Cr³⁺<span>&nbsp;</span>with cathodoluminescence (CL) spectral features in jadeite using point spectrometry, with more recent connections made via 2D CL spectrum imaging [<span id="jumplink-ozae044.009-B11 ozae044.009-B12 ozae044.009-B13" class="xrefLink"></span><a class="link link-ref link-reveal xref-bibr" data-open="ozae044.009-B11 ozae044.009-B12 ozae044.009-B13" data-google-interstitial="false">11-13</a>]. In this effort, we are seeking to establish whether Cr impurities are correlated with green coloration in jadeite using micro-scale (≤110 μm) visible-near infrared (VIS-NIR) reflectance spectrometry.</p> application/pdf 10.1093/mam/ozae044.009 en Oxford University Press Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry article