Locality: Palermo Mine Groton, NH
Specimen Size: 0.9 mm field of view
Field Collected: Unknown
Catalog No.:
Notes: Label says collected in 1973.
Locality: Palermo Mine Groton, NH
Specimen Size: Two views. 0.6 mm field of view, top photo
Field Collected: Unknown
Catalog No.: u2589
Notes:
Locality: Palermo Mine, Groton, NH
Specimen Size: 3.2 mm field of view
Field Collected: Clayton Ford
Catalog No.: u2650
Notes: This lumpy ball form of jahnsite is common in Groton, NH pegmatites.
Two high count, polished grain, EDS analyses indicated a chemistry of (4 P normalization):
BC453A: Ca0.73(Fe1.96,Mn0.36)Σ2.57Mg0.56Al0.07P4O26
BC453: Ca1.13(Fe1.81,Mn0.57)Σ2.53Mg0.38K0.02P4O30.3
With Fe > Mn and Mg present, jahnsite group members jahnsite-(CaFeMg) or jahnsite-(CaMnMg) are suggested. I suspect intermediate compositions between these two defined species are allowed, which would best fit the BC453 chemistry.
Locality: Palermo Mine, Groton, NH
Specimen Size: 1.2 mm field of view
Field Collected: Bob Wilken
Catalog No.: A Bob Wilken specimen and photo
Notes:
Locality: Fletcher Mine, Groton, NH
Specimen Size: 2 mm field of view
Field Collected: Bob Janules
Catalog No.: A Bob Janules specimen
Notes: This jahnsite is more yellow than most from Groton pegmatites. Found in a small vug in rockbridgeite.
Locality: Fletcher Mine, Groton, NH
Specimen Size: 1.2 mm field of view
Field Collected: Bob Janules
Catalog No.: A Bob Janules specimen
Notes: The Fletcher Mine is the type locality for jahnsite-(CaMnFe). Unknown if this specimen is that specific species.