Diopside

A thin, platelike specimen of pale gray, coarse-grained, graphitic marble neatly bisected by a layer 2.5 to 3 cm thick of fine-grained, straw-yellow diopside. The diopside fluoresces bright medium blue SW, appearing much like scheelite. This specimen came from the adit level of the Sterling mine during blasting operations for the Edison Tunnel in the 1990s and was acquired at that time by Richard Bostwick, who donated it to the Franklin Mineral Museum on August 4, 2024. It is probably one of those displayed in the large fluorescent tent during the 2007 Springfield, Massachusetts mineral show, when 13 cases of fluorescent minerals were a featured attraction.

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