"Multi-wave" calcite from the Grant Quarry, near Greely, Ontario
The Grant Quarry, located in the area of 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 minerals locality. But in 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've 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 slighly 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 an hydrocarbon of some sort, fluoresces a bright yellow under longwave.
I personnally never had a chance to collect there myself, since the quarry is closed to collectors since 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 pretty nice under UV. The matrix is covered with iridescent pyrobitumen, adding a bit of beauty to the specimen in white light. It measures 10,8 cm X 7,6 cm X 3,5 cm.
Longwave UV fluorescence, showing the typical orange response of the calcite from this locale.
Midwave UV fluorescence
Shortwave UV response.
Same specimen, shown in visible light.