Manganberzeliite is a sodium calcium manganese arsenate mineral, related to the garnet group. In an analysis by Jun Ito; the small amount of Si is likely part of the composition of the mineral and not due to contamination. Numerous unpublished analyses by [Dunn] show that Franklin manganberzeliite has the following compositional ranges: SiO2 0.4-0.6, Al2O3 0.0-0.5, FeO 0.4-0.6, MgO 1.5-2.6, CaO 18.9-19.4, Na2O 4.9-5.3, MnO 19.2-20.9, ZnO 0.0-1.0, and As2O5 53.1-55.9 wt. %.
Manganberzeliite was first described from Franklin by Frondel and Ito (1963); it has not been found at Sterling Hill.
Manganberzeliite occurs as massive granular material in veins. It is orange-yellow, with vitreous luster, and a density of 4.21 g/cm3. There is no discernible fluorescence in ultraviolet. It is best verified using both optical and X-ray methods.
Manganberzeliite occurs as veins up to 15 mm wide in franklinite/willemite ore. The veins are simple ones, either with manganberzeliite alone, or with a thin rim of calcite adjacent to the ore. John L. Baum (pers. comm.) considered this occurrence to be of limited extent, an observation supported by the closely agreeing analytical data for different specimens.
Another Franklin assemblage, represented by fewer specimens, consists of highly calcic ore cut by a vein. The vein filling has calcite and willemite at its margins, followed by a mixture of pink sarkinite and white hedyphane; the center of the vein is composed of manganberzeliite. Schallerite is present as very small crystals in calcite. (Dunn, 1995)

 Location Found: Franklin
 Year Discovered: 1894
 Formula: (Ca,Na)3(Mn2+,Mg)2(AsO4)3
 Essential Elements: Arsenic, Calcium, Manganese, Oxygen
 All Elements in Formula: Arsenic, Calcium, Magnesium, Manganese, Oxygen, Sodium
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
 To find out more about this mineral at minDat's website, follow this link   Manganberzeliite

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.673

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.66

The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 4, No. 2 - August 1963, pg. 9Manganberzeliite
View IssueV. 1, No. 1 - February 1960, pg. 9Manganberzeliite (small article)

Manganberzeliite, willemite and franklinite from Franklin, NJManganberzeliite, willemite and franklinite from Franklin, NJ under shortwave UV Light
Manganberzeliite (light to honey yellow, gemmy), willemite (white to green) and franklinite (black) from Franklin, NJ. From the collection of, and photo by Robert A. Boymistruk.
Manganberzeliite, willemite and franklinite from Franklin, NJ under shortwave UV light. The willemite fluoresces green, the franklinite and manganberzeliite are non-fluorescent. From the collection of, and photo by Robert A. Boymistruk.

Manganberzeliite, willemite, franklinite and calcite from Franklin, NJ
Manganberzeliite (honey yellow), willemite (light green), franklinite (black) and calcite (white) from Franklin, NJ. 4" x 2 5/8". From the collection of, and photo by Robert A. Boymistruk.

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