"Multi-wave" Calcite - Grant Quarry, near Greely, Ontario
Contributed by: FMS Admin
minID: 87R-0CM
Date: May 18th, 2026
Locality: Grant Quarry (Ottawa; Miller; Beaver Asphalt), Gloucester Township, Ottawa, Ontario, Canada (See on Mindat)
Size: 7.6 x 3.5 x 10.8 cm
Description:
The Grant Quarry, located near Greely in South-Eastern Ontario, Canada, is mostly known for its highly aesthetic quartz crystals, which are quite reminiscent of those from the Herkimer County in New York, as well as calcite and dolomite; but it's not generally known as a fluorescent mineral locality. But on some occasions, calcite specimens from this locality show an interesting reaction to UV (mostly longwave and midwave; the shortwave response is usually quite dim); and what makes them interesting is the fact that they fluoresce a different color under each wavelength. Under longwave, the most common response I have seen is a moderately bright orange; in some cases, the calcite fluoresces a very weak red under LW. The midwave response is the most interesting in my opinion; it is slightly brighter than longwave, and either purplish pink or pink; and under shortwave, the calcite usually fluoresces a rather weak peach color. Oftentimes, underneath the calcite crystals, a thin layer of what I assume to be a hydrocarbon of some sort, fluoresces a bright yellow under longwave.
I personally never had a chance to collect there myself, since the quarry has been closed to collectors for a few years; but I obtained a nice assortment of specimens via a friend of mine who had the chance to collect there in the 80s and early 90s. The specimen shown here is one of the best fluorescent Greely specimens I have in my collection. Not the most impressive calcite crystals in white light, but nice under UV. The matrix is covered with iridescent pyrobitumen, adding a bit of beauty to the specimen in white light.
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: Orange
- Fluorescence under Midwave (305nm LED) UV light: Violet
- Fluorescence under Shortwave (255nm LED) UV light: Orange