Anorthite, a calcium aluminum silicate mineral of the feldspar group, was first reported from the Franklin Marble in the Fowler Quarry near a contact with pegmatite by Warren (1901). Here it occurred as euhedral, tabular, blue-white crystals up to 7x3x1 cm in size.
A recalculated analysis of this near end-member material is given by Palache (1935). Anorthite was also reported from the Franklin Marble occurrence of margarite, close to the Sterling Hill orebody, by Cook (1973), Frondel (1972), and Dunn and Frondel (1990). Superb, euhedral 1 cm blackish crystals have been found in one of the local quarries, but it is not known which one; fine specimens are at Harvard University. Anorthite is not known from the orebodies. (Dunn, 1995)

 Location Found: Franklin and Ogdensburg
 Year Discovered: 1823
 Formula: CaAl2Si2O8
 Essential Elements: Aluminum, Calcium, Oxygen, Silicon
 All Elements in Formula: Aluminum, Calcium, Oxygen, Silicon
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Fluorescent Mineral Properties

 Shortwave UV light: Pale yellow
 Additional Information: Rare, associated with corundum. Franklin Marble assemblage.
 To find out more about this mineral at minDat's website, follow this link   Anorthite

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.508

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.41

The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 57, No. 2 - Fall 2016, pg. 12Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Anorthite
View IssueV. 32, No. 1 - Spring 1991, pg. 8An Uncommon Margarite/Corundum Assemblage From Sterling Hill, New Jersey, Pete J. Dunn, Clifford Frondel, Anorthite (small description)
View IssueV. 15, No. 2 - August 1974, pg. 10Fluorescent Corner - Anorthite
View IssueV. 13, No. 2 - August 1972, pg. 11The Fluorescent Minerals of Franklin/Ogdensburg Area by Frank Z. Edwards - Anorthite (Fluorescent Info)
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