Confidence: 4
Chemistry: Ca2(Mg,Fe)(Mg,Fe,Al)4Be4(PO4)6(OH)4 · 6H2O
Locality: Palermo Mine, N. Groton,, NH
Specimen Size: Top photo - 1.5 mm field of view. Bottom photo - 3 mm field of view.
Field Collected: Bob Wilken
Catalog No.: A Bob Wilken specimen and photo
Analysis: Segelerite was Bob's initial choice from the EDS analysis, PAL134.
Chemistry from EDS analysis: Ca2Mg2.23(Fe1.90,Mn0.25)(PO4)6.52O50 , normalized for 2 Ca.
A reasonably good fit for segelerite, with some Mn substituting for Fe, a bit high on the P and ignoring the bit of Ti & Ba. Allocation of O between (OH) and dot H2O unknown.
Visually, this segelerite is a good match for several mindat.org photos of this species, particularly mindat segelerite photo .
However a 2019 study of Palermo zanazziite, a beryllium mineral, that included reviews by Jim Nizamoff, convinced Bob that zanazziite was the best ID choice. Note that Be is not detectable by EDS.
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 2.8 cm specimen
Field Collected: Tom Mortimer - 1997
Catalog No.: 217
Notes: This specimen has been in the NH Species Display as Fairfieldite for several years. It was visually identified by Bob Whitmore as fairfieldite. I understood that this was the spherical form of Fairfieldite referred to in Bob Whitmore's book, The Pegmatite Mines Known as Palermo. A first polished grain EDS analysis (BC77) indicated a Ca, Mg, Fe, phosphate with a Ca:Fe:Mg:P ratio of 2:1:1.4:5. No Mn was detected, essential for fairfieldite. Fairfieldite chemistry is: Ca2(Mn2+,Fe2+)(PO4)2 · 2H2O
One species possibility is segelerite: CaMgFe(PO4)2(OH) · 4H2O , but the cation ratios are off.
A second polished grain EDS analysis (BC77a) of one of these white balls gave a result for which suggested collinsite. Collinsite chemistry is: Ca2(Mg,Fe2++)(PO4)2 · 2H2O
The analysis suggests a chemistry (normalized for 2 P): Ca0.86(Mg0.41,Fe0.57)(PO4)2 ... but the Ca is low and the result is deficient by about 8 oxygen for collinsite. Jim Nizamoff opined (6/17) that this specimen "has too much Fe to be a viable candidate" for collinsite.
These radial balls show color zoning so perhaps the chemistry varies along the radius.
A detailed 2019 investigation of this specimen, including additional EDS testing and Raman analysis, concluded this is zanazziite. A pdf of an article on this study was published in the April, 2019 MMNE newsletter, and is available here: Zanazziite Identification (pdf)
Locality: Palermo #1 Mine, N. Groton, NH
Specimen Size: 1 mm field of view
Field Collected: Jim Nizamoff
Catalog No.: u2095
Notes:
Locality: Palermo #1 Mine, N. Groton, NH
Specimen Size: 4.5 mm field of view
Field Collected: Bob Janules
Catalog No.: 1729
Notes: Moraesite and pale green beryl are also present on this TN specimen.
Locality: Palermo #1 Mine, N. Groton, NH
Specimen Size: 4 mm field of view
Field Collected: Bob Janules
Catalog No.: 1729
Notes: Moraesite and pale green beryl are also present on this TN specimen.
Locality: Palermo Mine, Groton, NH
Specimen Size: 1.2 mm field of view, top photo
Field Collected: Bob Wilken
Catalog No.: A Bob Wilken specimen
Notes: A visual ID by Jim Nizamoff