Monohydrocalcite, a calcium carbonate hydrate mineral, was reported by Dunn (1979c) from Sterling Hill; it has not been found at Franklin. It occurs as light green to light yellow-green rounded masses up to several cm in size (resembling drippings) with an internal fibrous texture, encrusting calcite. It resembles hyalite opal at first glance.
Monohydrocalcite was verified using X-ray powder diffraction methods and microprobe analysis which showed only Ca, with no Mg, Fe, Mn, or Zn present in detectable amounts. It is fluorescent in longwave and shortwave ultraviolet with a green color. It is a post-mining mineral which occurs as a dripstone on the walls of adits and shafts.
A second occurrence was reported from Sterling Hill by Jenkins (1994) who described it as white, microbotryoidal crusts on calcite and epidote. (Dunn, 1995)

 Location Found: Ogdensburg
 Year Discovered: 1959
 Formula: CaCO3 · H2O
 Essential Elements: Calcium, Carbon, Hydrogen, Oxygen
 All Elements in Formula: Calcium, Carbon, Hydrogen, Oxygen
 IMA Status: Approved 1964
Fluorescent Mineral Properties

 Shortwave UV light: Green, moderately bright
 Additional Information: Phosphoresces white
 To find out more about this mineral at minDat's website, follow this link   Monohydrocalcite

Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.622

The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 58, No. 1 - Spring 2017, pg. 13Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 2, Richard C. Bostwick - Monohydrocalcite
View IssueV. 35, No. 1 - Spring 1994, pg. 21Geology and Mineralogy of a Veinlet Assemblage Associated With Wollastonite-Bearing Rocks, Sterling Mine, Ogdensburg, New Jersey, Robert E. Jenkins II - Monohydrocalcite
View IssueV. 33, No. 2 - Fall 1992, pg. 11The Check List of Franklin-Sterling Hill Fluorescent Minerals - Monohydrocalcite (Fluorescent Info)
View IssueV. 20, No. 2 - September 1979, pg. 7Contributions to the Mineralogy of Franklin and Sterling Hill New Jersey, Monohydrocalcite (small article)
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