Barylite under shortwave UV Light

This photograph (same specimen as in photo BYL5a) duplicates what Charles Palache saw, when, in his 1935 monograph, he described barylite as showing a “vivid blue fluorescence” under the iron arc. In succeeding decades, however, as shortwave mercury-vapor ultraviolet (UV) lights replaced iron arc spark units, Palache’s statement led some hobbyists to believe that their specimens of margarosanite disseminated in feldspar were barylite, and specimens so labeled are still seen in some older collections. Moreover, to add to the confusion, true barylite shows almost no response to modern shortwave UV lights; the fluorescence is dim at best. The record was finally set straight in the fall 1993 issue of The Picking Table, in which Richard Gaines and Richard Bostwick discussed the fluorescence of barylite under different UV light sources and proved Palache correct.

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