Locality: Rt. 11 storm drain excavation, near Lake Shore Park, Gilford, NH
Specimen Size: 0.4 mm hexagonal, reddish, zoned, Synchysite-(Ce) crystal.
Field Collected: Clayton Ford, (#MM-262). Acquired by Gordon Jackson 8/16/04. Gifted to Tom Mortimer 6/09.
Catalog No.: u954
Notes: This is my NH species display specimen. Original photo taken in 2010 is improved here. Crystal prism is lying horizontally on matrix with hexagonal pinacoid visible on left.
Clayton Ford had identified this crystal as corundum. Corundum is reported from the Belknap Mountains area which includes the area where this specimen was found. This specimen is one of three acquired by Gordon Jackson, 8/16/04.
An EDS analysis of this specimen was done in September 2009, (EDS # M39), The opinion of the EDS analysist of this specimen was that it is Synchysite-(Ce). The EDS plot shows a Nd peak almost as high as the Ce peak, indicating that it is not distant from the Synchysite-(Nd) species.
The plot Th peak is higher than either the Ce or Nd peaks, perhaps suggesting Thorbastnasite with chemistry Th(Ca,Ce)(CO3)2F2·3H2O.
The high silicon peak (Si) at 1.75 KeV may be due to surface silica contamination, as this is not a polished grain analysis. Synchysite does not contain Si, so an ID concern remains.
Locality: Ham Weeks Quarry, Wakefield, NH
Specimen Size: 3 mm fov. Amber parisite crystals. Horizontal xls on left are zoned on the c axis.
Field Collected: Gene Bearss
Catalog No.: 1712
Notes: This, and several other similar specimens, were originally identified as parasite-(Ce). Reference: Rocks & Minerals Vol. 66 No. 2, March/April 1991, "The Weeks Pegmatite Mine" Smith & Bearss pgs 129-135.
"Parisite, Ca(REE)2[F2|(CO3)3] has been tentatively identified from the Weeks pegmatite by its physical properties (Bearss, 1994). It occurs embedded in feldspar with fluorite as small brown tapering crystals with a hexagonal outline and a greasy to glassy luster. The crystals react to heated hydrochloric acid, releasing carbon dioxide. They have a hardness specific gravity, and fusibility test that is consistant with parisite. The identity of the mineral has not been confirmed by X-ray defraction." Parisite is closely related to the synchesite mineral group.
The previous inclusion of the parisite species on the New Hampshire list was due solely to the above noted occurrence at the Weeks Mine in Wakefield.
An EDS analysis of this specimen was done in February 2010. This analysis showed the species to be Synchysite-(Ce), not Parisite-(Ce). For synchysite, the Ca:REE ratio must be near 1:1. For parisite the ratio should be 1:2.
This specimen proved very difficult to yield a satisfactory photograph. Four stacks of six images were processed with the Helicon stacking software. This photo was the best result, but is still not particularly good.
Locality: Pike Quarry, Hooksett, NH
Specimen Size: 1 mm synchesite crystal
Field Collected: Bob Wilken - 2014
Catalog No.: A Bob Wilken specimen
Notes:
Locality: Parker Mtn., Strafford, NH
Specimen Size: Largest hex tablet: 0.4 mm
Field Collected: Unknown - From MMNE 2018 symposium sales table
Catalog No.: u2247
Notes: Multiple probings of a November 2018 tiny crystal on carbon tape (BC298 - set 21) gave ambiguous and inconsistent results: EDS analysis . I think the Ca is legit. The unlabeled mush around 1.7 to 1.8 KeV may be silicon. The peak just above O may be F. All that can be said from this analysis is that it is an interesting REE mineral. A photo of the label on the micro-box as purchased is included.
A February, 2019 polished grain EDS analysis , (BC321 - set 23) gave synchysite-Ce the "best fit". So I will catalog this as synchysite-Ce. Tan hex tablets are a common form for synchysite-(Ce). The REE content quantified from this analysis is quite low for synchysite-(Ce). However, parasite-(Ce), another Ca-REE mineral, has twice the REE-Ca ratio.
Locality: Pike Hooksett Quarry, Hooksett, NH
Specimen Size: 0.6 mm crystal
Field Collected: Bob Wilken
Catalog No.: A Bob Wilken specimen and photo
Notes: The green color is unusual for a NH synchysite.