Root Beer Fluorite, Graymont Quarry, Genoa, Ohio
Contributed by: Chris Clemens
minID: J8A-M13
Date: Apr 18th, 2026
Locality: Graymont Dolime (OH) Inc. Quarry, Clay Township, Ottawa County, Ohio, USA (See on Mindat)
Size: 7.1 x 6.7 x 10.5 cm
Weight: 477 g
Description:
This large specimen from the Graymont Quarry in Genoa, Ohio features colorless, transparent fluorite cubes with root beer brown, zoned centers on a light grey limestone matrix. There are also some white bladed celestine crystals present. As shown in the photographs below, the fluorite is brightly fluorescent and phosphorescent under UV. The fluorescent response is activated by organic inclusions in the fluorite crystals.
The Graymont Quarry (aka Graymont Dolime Quarry, Genoa Quarry) is a well-known producer of beautiful fluorite specimens. This active quarry has been in operation since the late 1800's, and produces lime products and construction aggregate.
Bright white, zoned fluorescence is seen in the fluorite cubes when viewed under shortwave UV (254 nm). Note that the limestone matrix is also moderately fluorescent. Following exposure to shortwave UV (254 nm), pale blue/green phosphorescence is seen.
As is typical for root beer fluorite from northwest Ohio, this specimen shows its brightest fluorescent response under longwave UV (365 nm). Note that the response is warmer than seen under shortwave UV. Pale yellow phosphorescence is seen following exposure to longwave UV (365 nm).
Originally posted by Chris Clemens on Nature's Rainbows in 2020.
Summary of luminescence responses:
Fluorite (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
- Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Blue
- Fluorescence under Longwave (365nm LED) UV light: White
- Afterglow after exposure to Longwave (365nm LED) UV light: Yellow