Shown here is a pretty nice cabinet-sized specimen of calcite with dolomite, on a dolostone matrix, found near the town of Salaberry-De-Valleyfield in south-western Quebec, Canada. Some very small clear quartz crystals are also present, as well as a dusting of specular hematite on the calcite crystals. Only the midwave response is shown here, because SW is very weak, and LW is also too dim to be worth showing. Really nice both under MW and in daylight; the doubly terminated crystal roughly in the middle of the specimen is quite aesthetic. All other crystals are complete, except the one on the lower left, which is cleaved at the base.
Size: 7,6 cm X 7,5 cm X 5,2 cm
Largest crystal: 52 mm
Midwave UV (302 nm) response of the calcite. Not the brightest in my collection, but still pretty nice.
Same specimen, in visible light.