Locality: Palermo Mine #1, Pod 3, N, Groton, NH
Specimen Size: 2 cm specimen with lustrous, black, blocky-curved Rockbridgeite crystals to 0.5 mm.
Field Collected: Tom Mortimer
Catalog No.: U917
Notes:
Locality: Palermo Mine, N, Groton, NH
Specimen Size: 0.8 mm sphere of rockbridgeite
Field Collected: Walter Lane - from boxes of unsorted Palermo material purchased by the MMNE 2011
Catalog No.: TBC
Notes:
Locality: Palermo Mine, N, Groton, NH
Specimen Size: 1.7 mm broken sphere of dark-green rockbridgeite with red-brown jahnsite rind.
Field Collected: Walter Lane - from boxes of unsorted Palermo material purchased by the MMNE 2011
Catalog No.: TBC
Notes: Radial structure of botryoidal rockbridgeite is seen in sphere cross-sections.
Locality: Palermo #1 Mine, Pod 3, N. Groton, NH
Specimen Size: 1 mm field of view - prismatic rockbridgeite crystals
Field Collected: From small box of unsorted micros, gift of Bob Whitmore
Catalog No.: u1342
Notes: Deep red transparency observable in a few areas.
Locality: Palermo #1 Mine Pod 3, N. Groton, NH
Specimen Size: 3 cm specimen with mat of lustrous black 0.1 to 0.2 mm rockbridgeite crystals
Field Collected: Forrest Fogg
Catalog No.: u1440
Notes:
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 1.7 mm field of view
Field Collected: From a box of small rock chunks gifted by Bob Whitmore
Catalog No.: u1530
Notes: Nice, distinct rockbridgeite crystals on bed of granular rockbridgeite. Low contrast between crystals and background is a photographic challenge.
Locality: Valencia Mine, N. Groton, NH
Specimen Size: 4.5 cm rockbridgeite specimen with vug of botryoidal rockbridgeite
Field Collected: Dana Jewell
Catalog No.: NC
Notes: From a flat of Valencia Mine rocks donated by Dana Jewel at the November, 2014 Micromounters of New England meeting.
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 0.6 mm clump of rockbridgeite balls on mitridatite
Field Collected: From a tub of Palermo phosphate rocks gifted by Bob Whitmore
Catalog No.: u1889
Notes: EDS analyzed, BC64. The small amount of Si is likely a contaminant.
An early thought was that these dark balls might be dufrenite (reported from Palermo), but dufrenite requires a small amount of Ca. No Ca was detected in the EDS analysis. A modest amount of Mn indicates this is mangoan rockbridgeite. The webmineral.com analysis included in the link shows a favorable comparison with this specimen.
Locality: Palermo Mine, N. Groton, NH
Specimen Size: 5 mm field of view, top photo. Other FOV's as noted.
Field Collected: From a tub of Palermo phosphate rocks gifted by Bob Whitmore
Catalog No.: u1872
Notes: Rockbridge crystals embedded in messelite. There are many species on this specimen as indicated on last, annotated, photo (some small sprays of strunzite are also present).
I have had this specimen labeled as rockbridgeite for many years, mostly suggested (to me) by the black mass of crystals in the vug. Jim Nizamoff, on seeing my first photo of this piece in May, 2020, thought tourmaline was a better identification. Jim pointed out that the schorl illustrated in The Pegmatite Mines Known as Palermo is from Palermo #2, where it is more common. (Jim analized the Palermo #2 schorl.) Jim's opinion prompted a closer look and more photos that suggested a hexagonal shape of the embedded crystals.
To this point, I did not have a Palermo schorl specimen in my collection. It is likely moderately common in the pegmatite wall rock contact area, but few people, myself included, have bothered with this material. With the associated phosphate minerals on this specimen, it clearly came from the pegmatite interior.
So with continued uncertainty, I mailed off this specimen to Jim for a first-hand look. Jim replied:
"The black prismatic crystals are most definitely rockbridgeite. The white host is messelite. It is interesting that the photos made the messelite look like platy albite - having the ability to maneuver the specimen under the scope made it very easy to see that is was in fact messelite."
Locality: Palermo #1 Mine, N. Groton, NH
Specimen Size: 1.4 mm field of view
Field Collected: Bob Janules
Catalog No.: u1046
Notes: Distinct flat tabular crystals of rockbridgeite.