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SC164 - Corundum var Ruby

Size: 3 x 3 x 1 cm - Miniature (3-6 cm)
Weight: 22 g

Corundum/Ruby with unknown inclusions. The ruby fluoresce red under both 365nm led UV light and 404nm blue laser, but under 365nm led the inclusions fluoresce a nice bluish white, which is not visible under the 405nm laser.

Following, fluorescence spectra under different excitation wavelengths. The first one shows the Cr3+ strong line. It should be two lines at 693nm and 694nm, but my spectrometer cannot resolve them. The smaller lines before and after the main peak are also due to the Cr. The second spectrum is a scaled down version of the first, showing also lower wavelengths down to 400nm. The flat broad peak between 400nm and 500nm could be the unknown bluish white fluorescent inclusion, but I’m not sure (could be bleeding of the led light). The complex Cr peaks at ~700nm are also more visible in the second image.

Photo in normal light.
Fluorescence under longwave UV light (365nm LED).
Fluorescence under 405nm blue laser, with yellow filter.
Fluorescence spectrum under longwave UV light (365nm LED).
Fluorescence spectrum under longwave UV light (365nm LED).
Last update: 01 January 2021