Fluorescent Drill Core Sample from Nashville, Tennessee
Contributed by: Chris Clemens
minID: YQ6-TM4
Date: May 24th, 2026
Locality: Nashville area, Davidson County, Tennessee, USA (See on Mindat)
Size: 47 x 68 mm
Description:
This curious oddity is a fluorescent drill core specimen that was sampled from an Ordovician limestone bed on the West side of Nashville, Tennessee. The limestone is from the Fernvale member of the Sequatchie Formation, which is unique due to its karstic nature with lots of voids and small conduits which tend to trap petroleum. It is the petroleum that has permeated into the porous voids in the limestone that provides the fluorescent response under UV.
The drill core shows a bright, multi-colored, fluorescent response under full-wave UV (SW/254nm + MW/302nm + LW/365nm). The fluorescence is caused by petroleum and hydrocarbons that have permeated into the porous Fernvale limestone. The fluorescent response is similar under all UV wavelengths with only subtle differences in color and brightness.
Originally posted by Chris Clemens on Nature's Rainbows in 2022.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Yellow