Ganomalite



Ganomalite is a lead manganese calcium silicate mineral. Manganese was shown to be an essential constituent of ganomalite by Dunn et al. (1985a). There is little or no solid solution of other cations.
Ganomalite was first reported from Franklin by Dunn (1979b), and the species was subsequently redefined by Dunn et al. (1985a); it had previously been considered an analogue of nasonite, in error. It was further discussed, within the context of the other lead silicates from Franklin, by Dunn (1985b).
Preliminary details of the crystal structure of Franklin ganomalite were given by Dunn et al. (1985a). There are four large-cation sites with octahedral coordination, and Mn is ordered in a site of rank 1.
Ganomalite occurs as simple hexagonal, tabular, 0.5 mm crystals, mostly in arrays in subparallel growth; additional morphological observations and illustrations were given by Yeates (1991). It is colorless with adamantine luster; cleavage is indiscernible. There is no discernible fluorescence in ultraviolet. Local ganomalite is tentatively distinguished from nasonite by its tabular habit.
At Franklin, ganomalite occurs in andradite, associated with nasonite and clinohedrite; few specimens are known. Ganomalite crystals occur freely-formed within vugs and also enclosed within massive clinohedrite, the study of which revealed the coexistence of euhedral nasonite and ganomalite in contact. Aside from the above assemblage, ganomalite was seen in one anomalous specimen of the larsenite assemblage, associated with late-stage barysilite and larsenite in a vug. (Dunn, 1995)


 Location Found: Franklin
     
 
 Year Discovered: 1876
     
 Formula: Pb9Ca5Mn(Si2O7)4(SiO4)O
 Essential Elements: Calcium, Lead, Manganese, Oxygen, Silicon
 All Elements in Formula: Calcium, Lead, Manganese, 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   Ganomalite

     
 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.410


The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 33, No. 1 - Spring 1992, pg. 20The Lead Silicate Minerals of Franklin, New Jersey: an SEM Survey, Herb Yeates, Ganomalite
View IssueV. 28, No. 1 - Spring 1987, pg. 25Mineral Notes Research Reports, The Margarosanite Assemblage, Ganomalite
View IssueV. 26, Combined Issue 1985, pg. 13Mineral Notes Research Reports, Ganomalite
View IssueV. 20, No. 1 - March 1979, pg. 6New Minerals - Ganomalite
     
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