Sulfur on Calcite - Maybee, Michigan

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 (Maybee Quarry, Maybee, Monroe Co., Michigan). In the composite photo below, the specimen is shown under visible light (top image), SW UV (middle), and SW phosphorescence (bottom). Although the calcite dominates the UV response, the sulfur appears to show weak yellow/green fluorescence (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.

In the photograph above, the specimen is shown under visible light. Yellow sulfur crystals contrast against a background of small, colorless, transparent calcite crystals on a limestone matrix.

Fluorescence under short wave UV (254 nm).

Following exposure to short wave UV, the calcite shows strong and lasting pale blue/green phosphorescence.

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