Locality: Palermo Mine, N. Groton, NH
Specimen Size: 2.2 cm specimen with 8 mm zone of olive green arrojadite, left-middle.
Field Collected: Jim Nizamoff
Catalog No.: 1807
Notes: Arrojadite indicated by EDS analysis .
Raman spectroscopy analysis of two sample points (on the same polished mineral grain used for the EDS analysis) gave a good match for Arrojadite-(KNa). Arrojadite-(BaFe) is not in the Raman data base as of 12/12.
Dark blue mineral is vivianite, cream-colored mineral is siderite.
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 7 mm field of view
Field Collected: Jim Nizamoff
Catalog No.: u1234
Notes:
Locality: Chandlers Mill Mine, Newport, NH
Specimen Size: 5 cm specimen with zones of olive green arrojadite.
Field Collected: unknown
Catalog No.: Harvard University catalog # 126385
Notes:
Locality: Chandlers Mill Mine, Newport, NH
Specimen Size: A 6 cm specimen with pale green arrojadite group mineral embedded in feldspar.
Field Collected: ex Gene Bearss - Purchased from Perham's, West Paris, ME for $4.00
Catalog No.: 1951
Notes: Likely not dickinsonite, (as indicated on Perham's label) but another arrojadite group member. The arrojadite-dickinsonite group has undergone substantial revision since the 1960's. The Moore & Ito article, Alluaudites, wyllieites, arrojadite: crystal chemistry and nomenclature , June 1979 Mineralogical Magazine contains an analysis of a "Smith Mine" specimen indicating the species of this Smith Mine mineral is arrojadite, not dickinsonite.
Collectors not familar with arrojadite may easily mistake a specimen like this to be apatite.
The "Smith" Mine of Newport, NH has been clarified to be the Chandlers Mill Mine, see Chandlers Mill mines (pdf) - Fred Davis (2013)
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 2.2 cm specimen, 1.5 cm field of view. Pale gray-green granular arrojadite group mineral in tan-yellow siderite.
Field Collected: Walter Lane - MMNE give-away
Catalog No.: u2026
Notes: A non-stacked photo... not a lot to see here. An EDS analysis strongly suggests an arrojadite group mineral. This group has 14 members.
Arrojadite-(KFeNa) seems to be about the best fit.
The color and luster are consistent with typical arrojadite group minerals at Palermo. Some collectors might simply dismiss this as poor apatite, which it clearly is not.
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 1.5 mm vug opening - vertical
Field Collected: Bob Wilken
Catalog No.: A Bob Wilken specimen and photo
Notes: Arrojadite group crystals are rare.
[bw] EDS Atomic percents from EDS: O-48.57; Na-4.43; Mg-0.22; Al-0.47; Sr-0.07; P-18.60 K-0.24; Ca-1.46; Ba-0.97; Mn-9.38; Fe-15.60. Poor result w. IMA tool. Composition seems to fit an arrojadite, but which? Minor %’s of elements Sr, Ba, Al, K make it difficult to zero in on a specific sub-species. An Arrojadite of some kind likely.
Locality: Nancy Mine, N. Groton, NH
Specimen Size: 3.3 cm specimen of lustrous, glassy dark olive green, arrojadite
Field Collected: Clayton Ford - Label photo included.
Catalog No.: 2102
Notes: My card table of NH minerals at the 2018 Gilsum Rock Swap attracted the attention of Ken Leger of Milford, NH. Ken said he had acquired a small batch/collection of minerals (at a yard sale for $10.). He asked if I would take a look at them. I followed him back to his tailgate and he produced a small box of poly-bagged specimens. One bag had several glassy olive green specimens from the Nancy Mine with an accompanying Clayton Ford (1917-2001) label. Dickinsonite ! Phillip Morrill's New Hampshire Mines and Mineral Localities booklet (1960) lists dickinsonite for the Nancy Mine, (source likely M. Mrose). The arrojadite group (included dickinsonite) was expanded and re-defined in two American Mineralogist articles in 2006, many years after Morrill's booklet and Clayton's field collecting, so it is understandable how this got labeled as dickinsonite.
A polished grain EDS analysis (BC306) suggests this specimen is arrojadeite-(KNa) or arrojadite-(KFe).
The chemistry calculated from the atomic percents of this EDS analysis gives: K0.59Na2.01Fe7.26Mn1.77Ca1.37Mg0.46Al0.31P12O8.73 , normalized for 12 P. All the elements are present for an arrojadite group species, but the element ratios do not fit particularly well.
There are 15 (IMA approved) members of arrojadite group. For reference:
Dickinsonite: {KNa}{Mn2+[ ]}{Ca}{Na3}{Mn2+13}{Al}(PO4)12(OH)2
Arrojadite-(KNa): {KNa}{Na2}{Ca}{Na2[ ]}{Fe2+13}{Al}(PO4)11(HPO4)(OH)2
Arrojadite-(KFe): {KNa}{Fe2+[ ]}{Ca}{Na2[ ]}{Fe2+13}{Al}(PO4)11(HPO4)(OH)2
The "[ ]" vacancy slots may be filled by one or two monovalent cations (K, Na).
It is interesting that only one arrojadeite group member has any Mg as essential, fluorcarmoite-(BaNa). My specimen analysis had a moderate amount of Mg, but no Ba.
It is very satisfying to have acquired this specimen from the original NH "dickinsonite" occurrence. The Nancy Mine has been "off limits" for many years.
My NH display arrojadite is also from the Nancy Mine. It is much lighter green than this specimen. Its NH display arrojadite EDS analysis showed a moderate barium content suggesting arrojadite-(BaFe). An analysis with quantitative atomic percents would be informative for this specimen.
Postscript: A New Hampshire dickinsonite has been a sought after species by several fellow collectors for many years. It is most likely that dickinsonite, as now redefined by the IMA, does not exist in NH. Bob Wilken stated "trying to nail down a specific arrojadite seems to be next to impossible with EDS. I'm just happy if I can get in the "ballpark."
Locality: Palermo #1 Mine, Pod 1, N. Groton, NH
Specimen Size: 8 mm field of view
Field Collected: Bob Whitmore, 1975 per label, "***"
Catalog No.: A Ray Meyers collection specimen (purchased)
Notes: Identification per Bob Whitmore original label. [tm] These crystals are very dark for arrojadite.
Whitmore & Lawrence's book The Pegmatite Mines Known as Palermo states that "... arrojadite...was found exclusively at Pod 1 in hydrothermally reworked triphylite mixed with hagendorfite ..."
Locality: Palermo #1 Mine, Pod 1, N. Groton, NH
Specimen Size: 2.5 mm crystal
Field Collected: Bob Whitmore
Catalog No.: From a Ray Meyers collection specimen (purchased)
Notes: Identification per Bob Whitmore original label. This crystal broke from miniature specimen when shipped to me.
Locality: Palermo Mine, Groton, NH
Specimen Size: 5 mm green mass of arrojadite
Field Collected: From a tub gifted by Bob Whitmore
Catalog No.: u2543
Notes: A polished grain EDS analyses, BC356 Set 31, indicated an arrojadite group member as a best fit. Jim Nizamoff opined: "I think it would be wise to label these buggers as 'arrojadite group' for now."
The Arrojadite group presently (2021) has 16 members.
Locality: Palermo Mine, Groton, NH
Specimen Size: 2 cm field of view
Field Collected: From a tub gifted by Bob Whitmore
Catalog No.: u2542
Notes: A polished grain EDS analyses, BC352 Set 31, indicated an arrojadite group member as a best fit. This analysis had a bit of strontium, an element frequently found as aminor constituent in Palermo phosphates.
Triphylite, strunzite, laueite, pyrite, and wolfeite (or graftonite) are also present on this TN specimen. I could have trimmed this to micro-box size, but Jim Nizamoff stressed the importance of preserving the associated minerals.