Allanite-(Ce)



Allanite-(CE), is a calcium cerium aluminum iron silicate hydroxide mineral of the epidote group. It occurs as euhedral crystals, up to 25 mm in length, and tabular or bladed. The color is invariably black; the cleavages are imperfect to good; the luster is vitreous; and the density is 3.84 g/cm3. The crystals are extremely brittle, and few survive attempts to extricate them from matrix. Optically, it is nearly opaque, brown in thin fragments, and strongly pleochroic, with a mean index of refraction of 1.74.

Most Franklin allanite occurs as black, euhedral, bladed crystals embedded in green to whitish-green microcline; much of this material was found on the Trotter Dump, and inferior specimens are still abundant. The preponderance of the known specimens suggests a simple assemblage of microcline, allanite-(Ce), quartz, and minor andradite. The local abundance of this material indicates that the solutions from which allanite and microcline formed were relatively rich in Ce. There are few rare-earth minerals at these deposits; most of the rare-earth element concentration at Franklin is in allanite-(Ce). (Dunn, 1995)


 Location Found: Franklin
     
 
     
 Formula: {CaCe}{Al2Fe2+}(Si2O7)(SiO4)O(OH)
 Essential Elements: Aluminum, Calcium, Cerium, Hydrogen, Iron, Oxygen, Silicon
 All Elements in Formula: Aluminum, Calcium, Cerium, Hydrogen, Iron, Oxygen, Silicon
     
 IMA Status: Approved
     
     
 To find out more about this mineral at minDat's website, follow this link   Allanite-(Ce)

     
 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.403

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.40


The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 30, No. 1 - Spring 1989, pg. 8The Epidote-Pyroxene-Fluorapophyllite Assemblage in the Franklin Mine at Franklin, New Jersey, Philip P. Betancourt, Allanite (small description)
View IssueV. 29, No. 2 - Fall 1988, pg. 3Notes from the Laboratory & Changes to the List of Species From Franklin and Sterling Hill, Pete J. Dunn, John L. Baum, Nomenclature changes, Allanite-(Ce)
     
Images

     
Allanite-(Ce) in microcline from Franklin, NJ.
Allanite-(Ce) (dark brown) in microcline from Franklin, NJ. Field of view 3/4". From the collection of, and photo by WP.







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