"Optical" Calcite - Gatineau Area, Quebec, Canada
Contributed by: FMS Admin
minID: T8P-J5E
Date: May 13th, 2026
Locality: Gatineau TE, Outaouais, Québec, Canada (See on Mindat)
Size: 13 x 9.8 x 17.4 cm
Description:
The specimen shown here, while not having the most spectacular brightness, is still a nice display piece. Its transparency makes it look like a backlit gem when fluorescing under UV! It is at its best under midwave, followed by longwave. Shortwave is quite dim, therefore not worth being shown. The specimen is just bright enough to be worth being put in a midwave display. The midwave UV photo was taken using one of the new 310 nm high power UVB LEDs that just recently began popping up on the market. They're very efficient! For some reason, the longwave response is much brighter in the area that fluoresces pink under UVB.
The now depleted locality in which it was found produced large (up to about ten inches wide) rhombohedral crystals, which unfortunately were badly etched; this specimen comes from one of these large crystals, that was broken into smaller pieces to reveal the internal clarity of this material. Some of the best crystals were left intact, but the one from which this specimen came had lots of surface bruising and scratches.
Originally posted by Frédéric Messier Leroux on Nature's Rainbows in 2021.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Red
- Fluorescence under Midwave (305nm LED) UV light: Pink