GYPSUM

Gypsum, a calcium sulfate hydrate mineral, was first reported on one specimen each from Franklin and Sterling Hill by Palache (1928a, 1935). Frondel (1972) reported that it had subsequently been found in abundance.
Local gypsum is largely unstudied. Colorless clear cleavage plates and crystals over 10 cm are known to occur at Sterling Hill, but much massive white material may lie in collections unrecognized. Bostwick (1982) reported a moderate pale blue to white fluorescence in shortwave ultraviolet. Gypsum is most commonly associated with calcite in vein assemblages and locally may be associated with anhydrite or other minerals. In addition to the two specimens mentioned by Palache, gypsum has also been found on the 1500 and 1750 levels at Sterling Hill and as a white powder associated with hancockite, clinohedrite, and andradite from Franklin. It is part of the surficial alteration of charlesite. (Dunn, 1995)

Location Found:

Franklin and Ogdensburg

Formula:

CaSO₄ · 2H₂O

Essential Elements:

Calcium, Hydrogen, Oxygen, Sulfur

All Elements in Formula:

Calcium, Hydrogen, Oxygen, Sulfur

IMA Status:

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"

Fluorescent Mineral Properties

Shortwave UV light:

Moderately bright to weak white, pale yellow, and blue

Mid wave UV light:

Moderately bright to weak white, pale yellow, and blue

Longwave UV light:

White, pale yellow, blue

Additional Information:

Phosphoresces moderately bright to weak white, pale yellow, and blue. Weaker fluorescence at longwave

To find out more about this mineral at minDat's website, follow this link Gypsum

References:

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.633

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.59

The Picking Table References

	PT Issue and Page	Description / Comment
View Issue	V. 57, No. 2 - Fall 2016, pg. 19	Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Gypsum
View Issue	V. 34, No. 2 - Fall 1993, pg. 14	Recent Mineral Finds From The Sterling Mine Ogdensburg, New Jersey - Gypsum, Brochantite
View Issue	V. 33, No. 2 - Fall 1992, pg. 10	The Check List of Franklin-Sterling Hill Fluorescent Minerals - Gypsum (Fluorescent Info)
View Issue	V. 18, No. 2 - September 1977, pg. 13	The Fluorescent Minerals of Franklin and Sterling Hill, NJ by Richard C. Bostwick - Gypsum
View Issue	V. 15, No. 2 - August 1974, pg. 8	Fluorescent Corner - Gypsum/Selenite/Quartz
View Issue	V. 7, No. 2 - August 1966, pg. 9	The Minerals of Sterling Hill 1962-65 by Frank Z. Edwards - Gypsum

Images


Gypsum (selenite) clear to white and franklinite with minor calcite from the Sterling Hill Mine, NJ. From the collection of, and photo by JVF.


Gypsum (selenite) clear to white, franklinite and calcite from the Sterling Hill Mine, NJ. 3 3/4" x 1 1/2". From the collection of, and photo by WP.		Gypsum (selenite), franklinite and calcite from the Sterling Hill Mine, NJ under longwave UV light. The gypsum fluoresces white to light blue, calcite deep red, and the franklinite is non-fluorescent. 3 3/4" x 1 1/2". From the collection of, and photo by WP.

Gypsum (selenite), franklinite and calcite from the Sterling Hill Mine, NJ under shortwave UV light. The gypsum fluoresces blue, calcite red-orange to orange, and the franklinite is non-fluorescent. 3 3/4" x 1 1/2". From the collection of, and photo by WP.

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