Terlingua-Type Calcite, Cave Stone Co. Quarry, Norristown, Indiana

Pink to white cleavage rhombs of Terlingua-type calcite on a limestone matrix, from the Cave Stone Co. Quarry, Norristown, Indiana. This calcite is described in Manual Robbins' book ("Fluorescence, Gems and Minerals Under Ultraviolet Light," 1994, p. 77) for its classic Terlingua-type fluorescence and Midwestern US location. Named for the location of the initial discovery of the type specimens in the mercury mines of Terlingua, Texas, a Terlingua-type fluorescent response is typified by calcite that shows bright blue fluorescence under short wave UV, followed by bright and lasting blue afterglow, and bright pink fluorescence under long wave UV (365 nm).


This specimen shows the classic Terlingua-type bright blue fluorescence with lasting phosphorescence under SW UV, and a bright pink response under LW UV. This is a beautiful fluorescent specimen from an uncommon Midwestern location. 112 x 58 x 54 mm, 369 gms.

As shown in the photo montage above, this Norristown calcite specimen shows a classic Terlingua-type fluorescent response under UV.

The above photograph shows the specimen under visible light.

Under short wave UV (254 nm), this specimen shows a classic Terlingua-type, bright blue/white fluorescent response.

After the short wave UV source is shut off, the specimen continues to phosphoresce brightly for several minutes.

Under long wave UV (365 nm), a beautiful, bright pink fluorescent response is seen.

62 views0 comments