Tiger Mountain Amber (Tukwila Fm./Renton Fm. [Boundary], Middle to Late Eocene)

- Subjects:
Three exceptional specimens of amber, recovered from exposures on Tiger Mountain, Washington State; this is the second of two videos detailing the specimens' natural fluorescent and phosphorescent responses: longwave UV light (Convoy S2 flashlight) was used in this entry. All were prepared by hand using a diamond needle file, 240 to 3,000 grit SiC sandpaper, and chromium oxide (ZAM compound) on a Selvyt microfiber cloth.

- Amber's Source Formations and Age:
The amber-bearing coal contained within the the Tiger Mountain, Tukwila, and Renton Formations spans a geologic timescale ranging from Middle to Late Eocene in age (~41.3-33.9 Ma).

- About Amber Phosphorescence:
Phosphorescence is the noticeably-extended emission of radiation from an illuminated subject, after the source of illumination has been removed; the atoms of certain hydrocarbons within the amber, when irradiated by high intensity UV wavelengths (LED or dedicated UV light sources), achieve a higher energy or "excited" state; the rotation of atoms becomes the opposite of their rotation in their grounded "non-excited" state, allowing for a longer release of radiation (light). The light emitted in fluorescence and phosphorescence is always a longer wavelength than the source of illumination.

*Regrettably, my camera could not record the full duration of the phosphorescence of these specimens, or all other specimens (Chiapas, Sumatra, Baltic, Claiborne, Dominican), for that matter; multiple tests on all three Tiger Mountain specimens showed an average response of nearly 8 seconds, after 4 seconds of sustained direct illumination. These results are comparable to that of the Chiapas amber specimen from one of my previous videos.

Source: https://file.dnr.wa.gov/publications/ger_ri21_strat_eocene_king_co.pdf