This specimen is 100% SiO2 in spite of the obvious inhomogeneity, and is an example of cathodo-luminescence from a stress-shocked quartz. The actual colors being fluoresced is not known, but might range from pinks to blue. An educated guess would be blue. Three levels of CL are observed; bright , medium and none. The dark regions may be SiO2 glass, but the structure is too fine to know for sure. The mechanism for bright CL is not known.
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