This specimen, which I've been told is rather large for the locality, is really attractive both under UV and in daylight. It fluoresces a...

Single ruby crystal, in calcitic marble, along with non-fluorescent graphite and a greenish mineral, which I assume is possibly olivine....

Pink corundum var. sapphire; Lục Yên District, Yên Bái Province, Vietnam 12 mm X 11 mm X 7 mm Shown below under longwave UV and visible...