Locality: Palermo Mine, N. Groton, NH
Specimen Size: 1.8 mm crystal group, mounted on toothpick
Field Collected: Bob Whitmore - 1981
Catalog No.: A Bob Whitmore specimen
Notes: This specimenn is the one illustrated in Bob Whitmore's book The Pegmatite Mines Known as Palermo (pg. 137).
Locality: Palermo #1 Mine, Pod 3, N. Groton, NH
Specimen Size: 1.2 mm field of view, top photo. 0.08 mm blocky, lemon-yellow, jahnsite-CaMnMn crystals on rockbridgeite.
Field Collected: Forrest Fogg ex. Gordon Jackson
Catalog No.: u1460
Notes: Jahnsite-CaMnMn indicated by EDS analysis . Bob Whitmore's book, The Pegmatite Mines Known as Palermo notes two species of the Jahnsite group as occurring at Palermo: Jahnsite-(CaMnFe): CaMn2+Fe2+2Fe3+2(PO4)4(OH)2 · 8H2O and
Jahnsite-(CaMnMn): CaMn2+Mn2+2Fe3+2(PO4)4(OH)2 · 8H2O .
For Jahnsite-(CaMnFe), the Ca:Mn:Fe:P ratios are 1:1:4:4
For Jahnsite-(CaMnMn), the Ca:Mn:Fe:P ratios are 1:3:2:4 , a much higher percentage of Mn, consistant with the EDS plot.
Locality: Fletcher Mine, N. Groton, NH
Specimen Size: 4 mm field of view. Yellow crystaline matrix is the jahnsite-(CaMnMn).
Field Collected: Clayton Ford, 1960's. Acquired by Gordon Jackson 9/22/03. Gifted to T. Mortimer 3/19/16.
Catalog No.: u1956
Notes: Pale yellow jahnsite-(CaMnMn) with lavender strengite ball and stubby black prisms of rockbridgeite
A polished grain EDS analysis (BC82) indicated a Mn > Fe, Ca, phosphate with a Mn:Fe:Ca:P ratio of about 2.5:1.8:1.1:4 An XRD analysis was attempted on this mineral, but the sample was to small to produce a useful result.
Additional EDS analyses (BC383, A) gave chemistries of (normalized for 4 P):
Ca0.88Mn1.7Fe1.09Al0.44P4F0.49O50
Ca0.84Mn1.73Fe1.04Al0.39P4F0.73O50
Jahnsite-(CaMnMn), {Ca}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2·8H2O comes closest to this chemistry.
I have struggled to get a satisfactory identification for this specimen. The aluminum and fluorine observed in the analyses are a bit bothersome. Several mindat.org photos of jahnsite-(CaMnMn) compare favorably with this Fletcher specimen.
Locality: Parker Mtn. Mine, Center Strafford, NH
Specimen Size: 0.8 mm jahnsite crystal cluster
Field Collected: Gene Bearss
Catalog No.: A Gene Bearss collection specimen
Notes: Formula above is for Jahnsite-(CaMnFe). The exact jahnsite species for this specimen is unknown.
Locality: Parker Mtn. Mine, Center Strafford, NH
Specimen Size: 4 mm field of view
Field Collected: Gene Bearss - 1979
Catalog No.: A Gene Bearss collection specimen
Notes:
Locality: Parker Mtn. Mine, Center Strafford, NH
Specimen Size: 0.5 mm jahnsite crystal group
Field Collected: Gene Bearss - 1979
Catalog No.: A Gene Bearss collection specimen
Notes: This specimen also has abundant leucophosphite crystals.
Locality: E.E. Smith Mine, Alexanderia, NH
Specimen Size: 3.0 mm fov.
Field Collected: Bob Wilken
Catalog No.: A Bob Wilken specimen
Notes: [bw] Very raggedly terminated xls. They look like a composite of parallel fibers which make you wonder if they are whitmoreite. The consistency with which these fibers glom together (twinning?) to form a compound xl resembling the general shape of a classic jahnsite xl leads me to believe it is just that. Second, the close association and intermixing with rockbridgeite is another reason to believe it jahnsite. Third, the tendency to terminate raggedly is often seen on jahnsite crystals.
Locality: Chickering Mine, Walpole, NH
Specimen Size: Larger central jahnsite crystal is 0.3 mm
Field Collected: Tom Mortimer
Catalog No.: u1691
Notes: Jahnsite is rare at the Chickering Mine.
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 0.4 mm jahnsite crystal
Field Collected: From a tub of Palermo phosphate rocks gifted by Bob Whitmore
Catalog No.: u1929
Notes: A stack of 7 images processed with Helicon Focus.
Locality: Rice Mine, N. Groton, NH
Specimen Size: The jahnsite group bowtie in this photo is only about 0.4 mm
Field Collected: Clayton Ford ±1970
Catalog No.: A Bob Wilken specimen and photo
Notes [bw] Visual ID.
Locality: Rice Mine, N. Groton, NH
Specimen Size: 1.3 mm field of view
Field Collected: Clayton Ford ±1970
Catalog No.: A Bob Wilken specimen and photo
Notes [bw] Visual ID.