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Much of the black tourmaline in the western part of New Hampshire has been analyzed to be the Dravite species.
Highslide JS
UVITE    Tower Hill Rhodonite Locale, Hinsdale, NH
9.5 cm specimen with dark brown uvite crystals in silvery-mica, and anthophyllite?, matrix

Species:           UVITE
Locality:          Tower Hill Rhodonite Locale, Hinsdale, NH
Specimen Size: 9.5 cm specimen with dark brown uvite crystals in silvery-mica, and anthophyllite?, matrix
Field Collected: Tom Mortimer
Catalog No.: 1480
Notes: This Hinsdale uvite was verified by EDS analysis, (see multiple analyses below).
Highslide JS
UVITE    Tower Hill Rhodonite Locale, Hinsdale, NH
Zoom view of 3 cm uvite crystal in specimen 1480.

Species:           UVITE
Locality:          Tower Hill Rhodonite Locale, Hinsdale, NH
Specimen Size: Zoom view of 3 cm uvite crystal in specimen 1480.
Field Collected: Tom Mortimer - May 5, 2005
Catalog No.: 1480
Notes: Uvite-Dravite suggested by initial EDS analysis. Note in the analysis plot, the Mg content is much higher than the Fe content.
A second EDS analysis of this tourmaline with an instrument with good light element capability indicated a small sodium peak at 1.04 KeV, (not labeled on plot). Sodium is an "essential element" for dravite. End member dravite does not have calcium, which is an "essential element" for uvite. Both plots for this specimen show modest calcium .... and also iron, a component of schorl tourmaline. The plots do clearly show a magnesium dominant tourmaline. Both dravite and uvite satisfy this criteria, but uvite has a significant calcium content.
A third EDS analysis of this tourmaline, (3/2/16), including ZAF corrected element atomic percents, showed a Ca dominance over Na, (> 7X) indicating Uvite tourmaline.
Webmineral emperical formulae for Dravite & Uvite derived from analyses are given below for comparison with the APFU computed from this last EDS analysis, (adjusted for 3.4% boron, not detectable by the instrument, as a "best fit"):
Dravite: NaMg3Fe0.75Al5(BO3)3(Si6O18)(OH)
Uvite:   Ca0.75Na0.25Mg2.25Fe0.75Al6(BO3)3(Si6O18)(OH)3F
#1480:   Ca0.57Na0.14Mg1.9Fe0.55Al4.7(BO3)2.55(Si6O17)(OH)0

Uvite was included Janet Cares' New Hampshire species list published in vol. 65, no. 4 (Jul,Aug 1990) Rocks & Minerals, but I have been unable to locate a literature reference to substantiate this claim. Neither Phillip Morrill's New Hampshire Mines and Mineral Localities nor Meyers and Stewart's Part III Minerals and Mines make a reference to NH uvite.
Highslide JS
DRAVITE    Island Mine, Alstead, NH
2 cm terminated dravite crystal.


Highslide JS
DRAVITE    Island Mine, Alstead, NH
2 cm terminated dravite crystal.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 2 cm terminated dravite crystal, two views with different lighting.
Field Collected: Tom Mortimer
Catalog No.: 519
Notes: The Na-Mg dominant tourmaline, dravite, verified by EDS analysis.
EDS detector counts: Na = 135, Mg = 245, Al = 1437, Si = 1460, Fe = 157.
Highslide JS
DRAVITE    Island Mine, Alstead, NH
2.8 cm dravite crystal pair with smaller crystal penetrating larger one at top.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 2.8 cm dravite crystal pair with smaller crystal penetrating larger one at top.
Field Collected: Tom Mortimer
Catalog No.: 518
Notes: Slight transparency of these crystals reveals the brownish coloration characteristic of the dravite species.The specimen has a number of small embedded garnet crystals, likely spessartine.
Highslide JS
DRAVITE    Island Mine, Alstead, NH
3.8 cm double terminated dravite "log" with terminated dravite crystal "branches".

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 3.8 cm double terminated dravite "log" with terminated dravite crystal "branches".
Field Collected: Kevin Mortimer
Catalog No.: KTM
Notes: A most unusual dravite crystal group from this locality.
Highslide JS
DRAVITE    Island Mine, Alstead, NH
3.5 cm cluster of terminated dravite crystals.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 3.5 cm cluster of terminated dravite crystals.
Field Collected: Kevin Mortimer
Catalog No.: KTM
Notes:
Highslide JS
DRAVITE    Island Mine, Alstead, NH
7 cm dravite specimen.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 7 cm dravite specimen.
Field Collected: Tom Mortimer
Catalog No.:
Notes:
Highslide JS
DRAVITE    Island Mine, Alstead, NH
4 cm specimen. Multiple terminated dravite crystals in muscovite.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 4 cm specimen. Multiple terminated dravite crystals in muscovite.
Field Collected: Tom Mortimer
Catalog No.:
Notes:
Highslide JS
DRAVITE    Island Mine, Alstead, NH
5 cm terminated dravite crystal.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 5 cm terminated dravite crystal.
Field Collected: Tom Mortimer
Catalog No.: 790
Notes:
Highslide JS
DRAVITE    Island Mine, Alstead, NH
6 cm cluster of parallel terminated dravite crystals.

Species:           DRAVITE
Locality:          Island Mine, Alstead, NH
Specimen Size: 6 cm cluster of parallel terminated dravite crystals.
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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