Here’s a rare specimen right out of Manual Robbins’ book (Fluorescence, Gems and Minerals Under Ultraviolet Light, 1994), pages 192 and 205. Sulfur on calcite from Maybee, Michigan. In this composite photo the specimen is shown under visible light (top image), SW UV (middle), and SW phosphorescence (bottom). Although the calcite dominates the show, the sulfur appears to show a weak yellow fluorescent response (see more on that below). The size of this specimen is 10.4 x 6.1 x 5.3 cm and it weighs 331 grams.
In the following larger images (below), showing fluorescence and phosphorescence under short wave UV, the sulfur appears to show a weak yellow/green fluorescent response. Analysis of this specimen showed that the sulfur is not visibly fluorescent, and that the apparent fluorescence of the sulfur is simply the result of the transmission of the fluorescent light emitted by the calcite through the translucent sulfur crystals.
Mouse over the scrolling images for wavelength information.