Clinochlore



Clinochlore, a magnesium aluminum silicate hydroxide mineral of the chlorite group, is found sparsely at both Franklin and Sterling Hill, and in the Franklin Marble.
Frondel and Ito (1975) reported, as pennine, pale rose-colored tiny crystals in a vug with sonolite in a veinlet cutting franklinite ore from Franklin. These crystals have a density of 2.74 g/cm3. The "chlorite" reported and illustrated from the Buckwheat Dolomite by Peters et al. (1983) is likely clinochlore. Clinochlore is not uncommon in very small amounts, occurring as a vug-liner or as isolated clusters of colorless or light green crystals. It occurs in the original baumite assemblage (Bailey and Guggenheim, 1989).
[Dunn] has found clinochlore as tiny light brown pseudohexagonal crystals associated with kraisslite from Sterling Hill. Reilly (1983) reported a chlorite similar to Franklin chamosite (the brunsvigite of Frondel and Ito, 1975) from Sterling Hill drill-hole #124, 15 feet from its beginning on the 340 level. However, this material is not Fe-rich and thus not chamosite. It is a manganoan, zincian, ferroan chlorite, here referred to as clinochlore tentatively. The chemical composition is approximately (Mg2.5Fe1.0Mn0.7Zn0.7)Al(Si3Al)O10(OH)8.
Yau et al. (1984) reported chlorite replacing phlogopite in the Franklin Marble, and replacements of diopside may exist as well. Clinochlore is also found in other assemblages, commonly as a late-stage mineral in sparse amounts. However, these have not been studied. (Dunn, 1995)


 Location Found: Franklin and Ogdensburg
     
 
 Year Discovered: 1851
     
 Formula: (Mg,Fe2+)5Al(AlSi3O10)(OH)8
 Essential Elements: Aluminum, Hydrogen, Magnesium, Oxygen, Silicon
 All Elements in Formula: Aluminum, Hydrogen, Iron, Magnesium, Oxygen, Silicon
     
 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   Clinochlore

     
 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.470


The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 51, No. 2 - Fall 2010, pg. 17Clinochlore From the Franklin, New Jersey Taylor Road Site
View IssueV. 32, No. 1 - Spring 1991, pg. 9An Uncommon Margarite/Corundum Assemblage From Sterling Hill, New Jersey, Pete J. Dunn, Clifford Frondel, Clinochlore (small description)
     
Images

     
Clinochlore, dolomite, calcite, franklinite, Taylor Road Dump, image width 1 inch
Clinochlore (non-fluorescent) metallic green, with dolomite (white), calcite (translucent white), and franklinite (black), from Taylor Road Dump, Franklin, New Jersey. Image width 1" (25 mm). Photo by WP.







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