Locality: Ham-Weeks Mine, Wakefield, NH
Specimen Size: 4.5 cm specimen with central zone of black columbite. Samarskite-(Y) is 1 to 2 mm thick resonous-brown zone on right edge of columbite, (yellow arrow).
Field Collected: Gene Bearss - 1979
Catalog No.: 1742
Notes: Samarskite-Y verified by EDS analysis.
A second analysis an XRF Analysis (pdf)) performed on a polished grain of the display specimen by Fred Davis also gave support to the Ham-Weeks Samarskite-(Y) identification.
Locality: Ham-Weeks Mine, Wakefield, NH
Specimen Size: 2.5 cm specimen with unknown cream-colored oxide.
Field Collected: Don Swenson
Catalog No.: 1486
Notes: This specimen is slightly radio-active. This specimen was previously in my display as Ishikawaite. However an October, 2011 EDS analysis and a Nov. 2, 2011 XRF Analysis (pdf) performed by Fred Davis showed this specimen to be samarskite.
A Raman spectroscopy examination of two sample points on this mineral grain reported:
Point 1: Fair match to yttropyrochlore, uranopyrochlore, ishikawaite.
Point 2: Poor match to ishikawaite; worse match to samarskite-(Y); no match to columbite-tantalite/tapiolite.
The Raman analyst noted that the Raman spectrometer gives poor, noisy, spectra for heavy metal oxides like samarskite, uraninite, and some columbite-tantalite series minerals.
Locality: N. Sugarloaf Mtn., Bethlehem, NH
Specimen Size: 3 cm specimen with black, sub-metalic samarskite-(Y) in feldspar.
Field Collected: Gene Bearss
Catalog No.: 2090
Notes: Polished grain EDS analyses (BC264 & BC279) indicated samarskite-(Y). There is an unlabeled Y peak between the Ta and Nb peaks. Fred Davis computed Ercit plots ( Ercit plot 1 , Ercit plot 2 ) from these analyses.
Locality: N. Sugarloaf Mtn. Bethlehem, NH
Specimen Size: 5.3 cm specimen with 1.3 cm jet black samarskite mineral at top.
Field Collected: Gene Bearss
Catalog No.: 2089
Notes: A polished grain EDS analysis BC275B, showed a Nb, Ta, Fe, Y, U, mineral. The tiny bit of Se is likely a miss-identification by the instrument element assignment software.
This specimen gives a moderate response on my scintillometer.
Fred Davis opined: "the general trend for quantities of elements [for this specimen] doesn't fit [samarskite] (Fe and Y+REE swap places, quantity-wise). Qualitatively, yes, the elements are present but including quantity takes the match process up a notch with a little more certainty. None of [these possible] species has that much iron. [summarizing]:
Yttrocolumbite Nb+Ta > Y+REE > U+Th > Fe
Petscheckite Nb+Ta > U+Th > Fe > Y+REE
Ishikawaite Nb+Ta > U+Th > Fe > Y+REE
Samarskite Nb+Ta > Y+REE > U+Th > Fe
[This] N. Sugarloaf Nb+Ta > Fe > U > Y "
Locality: Moat Mtn., Hale's Location, NH
Specimen Size: 1.2 mm high samarskite-(Y) cluster
Field Collected: Bob Janules
Catalog No.: A Bob Janules collection specimen
Notes: Bob supplied an EDS analysis for this specimen. The samarskite-Y is likely the dark brown mineral exposed on the lower broken surfaces.
Locality: Ham-Weeks Mine, Wakefield, NH
Specimen Size: 2.4 cm specimen
Field Collected: Gene Bearss
Catalog No.: NC - gifted
Notes: Specimen shows a black, sub-metalic, lump on feldspar matrix. Gene had this labeled as ishikawaite. Lacking a confirmed NH ishikawaite motivated an EDS analyses. This indicated the required elements for ishikawaite were present, but the uranium content was far too low. Fred Davis plotted the chemistry from this analysis on an Ercit plot that placed this specimen in the samarskite field, the blue "TJM" dot.
[fd] Ercit plots (The Canadian Mineralogist Vol. 43, pp. 1291-1303 2005) utilize "a statistical analysis of composition to generate two vectors - where they point is likely the id of the mineral as shown on a graphical plot. Within the 'samarskite' zone is a small region to the left where ishikawaite is found. The two ishikawaite points are from two analyses from HOM. Your data looks more like samarskite-(Y)." Fred
Locality: Ham-Weeks Mine, Wakefield, NH
Specimen Size: 2.4 cm specimen
Field Collected: Gene Bearss
Catalog No.: NC
Notes: Specimen shows a black, sub-metalic, lump on feldspar matrix. Gene had this labeled as ishikawaite. Lacking a confirmed NH ishikawaite motivated an EDS analyses. This indicated the required elements for ishikawaite were present, but the uranium content was far too low. Fred Davis plotted the chemistry from this analysis on an Ercit plot that placed this specimen in the samarskite field, the blue "TJM" dot.
[fd] Ercit plots (The Canadian Mineralogist Vol. 43, pp. 1291-1303 2005) utilize "a statistical analysis of composition to generate two vectors - where they point is likely the id of the mineral as shown on a graphical plot. Within the 'samarskite' zone is a small region to the left where ishikawaite is found. The two ishikawaite points are from two analyses from HOM. Your data looks more like samarskite-(Y)." Fred