Ellacoya Locality, Gilford, NH, Mineral Gallery              Return to mindatnh front page.            Click on image for larger view
This page is an alphabetical photo gallery of minerals from the Ellacoya Locality, Gilford, New Hampshire.   (A locality specific photo set from mindatnh.org)
22 species, 49 mineral photos

The Ellacoya locality is a pile of boulders blasted from the widening of Rt. 11 in Gilford, NH. It is located on the eastern side of the Belknap Mountains, across from the entrance to the Ellacoya state park.
This is believed to be an "open" site, however I [tm] have not visited this site in the last decade.
The paper bound book Stepping Stones across New Hampshire by Long & Roberts (Amazon $19.95, 2020) provides an excellent, well illustrated, tutorial on the geologic history and structure of the Belknap Mountains, the host rock body for the Ellacoya locality.
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Ellacoya Locality   Ellacoya Locality, NH
Aerial view of Bow locality

Locality:           Ellacoya Locality
Notes: Google Earth view. Rt. 11 at bottom.
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Ellacoya Locality   Ellacoya Locality, NH
2004 site photo

Locality:           2004 site photo
Notes:
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ACTINOLITE   Ellacoya Locale, Gilford, NH
1.2 mm field of view

Species:           ACTINOLITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.2 mm field of view
Field Collected: Tom Mortimer
Catalog No.: u2256
Notes: A polished grain EDS analysis (BC357) indicated actinolite. The APFU calculated from this analysis is Ca2(Mg2.1,Fe1.77,Al0.22)Si7.7O16.2 normalized for 2 Ca. The trace of neon is a bogie.
From analysis Mg/(Mg+Fe) = 0.55. This ratio must be less than 0.5 for ferroactinolite. So this is close to ferroactinolite.
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ACTINOLITE   Ellacoya Locale, Gilford, NH
3.5 mm field of view. Actinolite blades on feldspar.

Species:           ACTINOLITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 3.5 mm field of view. Actinolite blades on feldspar.
Field Collected: Tom Mortimer
Catalog No.: NC
Notes:
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ACTINOLITE   Ellacoya Locale, Gilford, NH
1.8 mm field of view. Stubby actinolite crystals in diorite vug.

Species:           ACTINOLITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.8 mm field of view. Stubby actinolite crystals in diorite vug.
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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ACTINOLITE var. Byssolite   Ellacoya Locale, Gilford, NH
14 mm field of view.

Species:           ACTINOLITE var. Byssolite
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 14 mm field of view.
Field Collected: Tom Mortimer
Catalog No.: u2372
Notes: Byssolite is a fibrous to hair-like crystal or mass of fibers frequently in theactinolite-tremoliteseries, but may be any amphibole species.
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ACTINOLITE - TREMOLITE   Ellacoya Locale, Gilford, NH
1.3 mm field of view.

Species:           ACTINOLITE - TREMOLITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.3 mm field of view. White end of crystals suggests zoning to tremolite.
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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ALBITE   Ellacoya Locale, Gilford, NH
14 mm field of view box-work crystal group


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ALBITE   Ellacoya Locale, Gilford, NH
14 mm field of view box-work crystal group

Species:           ALBITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 14 mm field of view box-work crystal group
Field Collected: Tom Mortimer
Catalog No.: NC
Notes:
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AUGITE   Ellacoya Locale, Gilford, NH
3 mm black augite crystal with Titanite, (orange)

Species:           AUGITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 3 mm black augite crystal with Titanite, (orange)
Field Collected: Tom Mortimer
Catalog No.: u869
Notes: EDS analysis indicates these black prisms are augite.
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AUGITE    Lockes Hill, Gilford, NH
1.2 cm augite crystal weathered from diorite matrix
Species:           AUGITE  
Locality:          Lockes Hill, Gilford, NH
Specimen Size: 1.2 cm augite crystal weathered from diorite matrix
Field Collected: Tom Mortimer
Catalog No.: 1481
Notes:
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CHABAZITE    Ellacoya Locale, Gilford, NH
10 mm cluster of milky, rhombic, chabazite crystals. Largest is 4 mm.
Species:           CHABAZITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 10 mm cluster of milky, rhombic, chabazite crystals. Largest is 4 mm.
Field Collected: Tom Mortimer
Catalog No.: u1131
Notes: Rhombic shape and luster of these crystals is characteristic of chabazite.
EDS analysis of similar crystals from the Ellacoya locale indicates the species is chabazite:
(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
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CHABAZITE    Ellacoya Locale, Gilford, NH
Largest crystal is 1.4 mm.
Species:           CHABAZITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: Largest crystal is 1.4 mm.
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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APATITE-(CaOH)   Ellacoya Locale, Gilford, NH
1.2 mm clear apatite crystal with internal reflections

Species:           HYDROXYLAPATITE - APATITE-(CaOH)
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.2 mm clear apatite crystal with internal reflections
Field Collected: Tom Mortimer
Catalog No.: u606
Notes: A polished grain EDS analysis indicated the hydroxylapatite species. No fluorine was detected by detector with good light element sensitivity down to carbon. The large peak in the plot at 277 eV is due to the carbon coating of the specimen block.
The Ellacoya apatite photo on mindat.org (by Scott Whittemore ) is labeled as Fluorapatite. A March 2005 EDS analysis of a clear Ellacoya apatite was done by Jim Nizamoff while at UNO, but the instrument used had no response below about 1.0 KeV, where fluorine, if present, would have registered.
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CLINOCHLORE    Ellacoya Locale, Gilford, NH
2.7 mm field of view
Species:           CLINOCHLORE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 2.7 mm field of view.
Field Collected: Tom Mortimer
Catalog No.: NC
Notes: Chlorite Group Clinochlore visual ID
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FLUORITE    Ellacoya Locale, Gilford, NH
2.7 mm field of view
Species:           FLUORITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 2.7 mm field of view.
Field Collected: Tom Mortimer
Catalog No.: u629
Notes: Fluorite is uncommon at the Ellacoya locality
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ORTHOCLASE var. Adularia    Ellacoya Locale, Gilford, NH
2.7 mm field of view
Species:           ORTHOCLASE var. Adularia
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 2.7 mm field of view.
Field Collected: Tom Mortimer
Catalog No.: e.g. u703
Notes: EDS analysis has shown these to be a potassium feldspar. Orthoclase assumed.
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ORTHOCLASE var. Adularia    Ellacoya Locale, Gilford, NH
1.2 mm field of view
Species:           ORTHOCLASE var. Adularia
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.2 mm field of view.
Field Collected: Tom Mortimer
Catalog No.: e.g. u703
Notes: EDS analysis has shown these to be a potassium feldspar. Orthoclase assumed.
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MAGNETITE    Ellacoya Locale, Gilford, NH
1.1 mm octahedron


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MAGNETITE    Ellacoya Locale, Gilford, NH
1.1 mm octahedron
Species:           MAGNETITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.1 mm octahedron, two views
Field Collected: Tom Mortimer
Catalog No.: u613
Notes:
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MICROCLINE   Ellacoya Locale, Gilford, NH
6 mm crystal
Species:           MICROCLINE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 6 mm crystal
Field Collected: Tom Mortimer
Catalog No.:
Notes: Drawing illustrates twinning.
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MOLYBDENITE   Ellacoya Locale, Gilford, NH
2 mm field of view
Species:           MOLYBDENITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 2 mm field of view
Field Collected: Tom Mortimer
Catalog No.: u607
Notes:
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OPAL var. Hyalite   Ellacoya Locale, Gilford, NH
3.5 cm field of view
Species:           OPAL var. Hyalite
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 3.5 cm field of view
Field Collected: Tom Mortimer
Catalog No.: u502
Notes: Daylight and SW UV views
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OPAL var. Hyalite   Ellacoya Locale, Gilford, NH
Opal on tip of quartz crystal, 1.1 mm globule
Species:           OPAL var. Hyalite
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: Opal on tip of quartz crystal, 1.1 mm globule
Field Collected: Tom Mortimer
Catalog No.:
Notes: Downward pointing quartz crystal. Gravity induced silica drip.
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PYRITE - altering to goethite   Ellacoya Locale, Gilford, NH
1.4 mm crystal (pyritohedron - pentagonal dodecahedron)
Species:           PYRITE - altering to goethite
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.4 mm crystal (pyritohedron - pentagonal dodecahedron)
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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QUARTZ with Microcline   Ellacoya Locale, Gilford, NH
4 cm field of view. Portion of 5 inch mairolitic cavity in granite
Species:           QUARTZ with Microcline
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 4 cm field of view. Portion of 5 inch mairolitic cavity in granite
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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QUARTZ   Ellacoya Locale, Gilford, NH
10 mm Tessin habit crystal
Species:           QUARTZ
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 10 mm Tessin habit crystal
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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QUARTZ   Ellacoya Locale, Gilford, NH
1.8 cm Tessin habit crystal
Species:           QUARTZ
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.8 cm Tessin habit crystal
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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PHLOGOPITE   Ellacoya Locale, Gilford, NH
Foreground mica crystal is 0.7 mm

Species:           PHLOGOPITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: Foreground mica crystal is 0.7 mm
Field Collected: Tom Mortimer
Catalog No.: u2173
Notes: This could be one of several dark mica species, but the nice hexagonal form initially suggested annite to me. An April 2018 carbon tape mounted grain EDS analysis (set 19, BC289) indicated a potassium, magnesium dominant (over iron) mica, so this is phlogopite. The chemistry from the analysis gave: (normalized for one atom of potassium)
K(Mg1.6,Fe1.3)Al1.3Si3.6O21.1Cl0.1. This is not too far from the phlogopite - annite midpoint. This is a reasonably satisfying analysis. For a phlogopite - annite mica, the Mg + Fe should add to 3, the Al should be 1 and the Si should be 3
Some greenish foliated balls of mica are also seen at this locality. These are likely a chlorite group species. The chlorite group micas do not have potassium.
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PHLOGOPITE   Ellacoya Locale, Gilford, NH
4 mm field of view

Species:           PHLOGOPITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 4 mm field of view
Field Collected: Tom Mortimer
Catalog No.: u2170
Notes:
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TITANITE    Ellacoya Locale, Gilford, NH
2 mm titanite crystal

Species:           TITANITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 2 mm titanite crystal
Field Collected: Tom Mortimer
Catalog No.: u618
Notes:
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TITANITE    Ellacoya Locale, Gilford, NH
1.4 mm titanite crystal

Species:           TITANITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.4 mm titanite crystal
Field Collected: Tom Mortimer
Catalog No.: u609
Notes:
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TITANITE    Ellacoya Locale, Gilford, NH
1.7 mm titanite crystal

Species:           TITANITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.7 mm titanite crystal
Field Collected: Tom Mortimer
Catalog No.: u530
Notes:
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TITANITE    Ellacoya Locale, Gilford, NH
2 mm titanite crystal

Species:           TITANITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 2 mm titanite crystal
Field Collected: Tom Mortimer
Catalog No.: u623
Notes:
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TITANITE    Ellacoya Locale, Gilford, NH
9 mm titanite crystal

Species:           TITANITE
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 9 mm titanite crystal
Field Collected: Tom Mortimer
Catalog No.: 1410
Notes: I believe this is the largest titanite crystal that has been found to date at the Ellacoya locale.
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UNDETERMINED    Ellacoya Locale, Gilford, NH
zoned, prismatic crystals. Maximum height is 0.01 m

Species:           UNDETERMINED
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: zoned, prismatic crystals. Maximum height is 0.01 m
Field Collected: Tom Mortimer
Catalog No.:
Notes:
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UNDETERMINED    Ellacoya Locale, Gilford, NH
1.5 mm green amphibole crystal

Species:           UNDETERMINED
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.5 mm green amphibole crystal
Field Collected: Tom Mortimer
Catalog No.: u600
Notes: EDS analysis suggested the species ferri-tischermakite to analyst Kerry Day, based on the Fe > Ca in comparison to epidote EDS analysis.
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UNDETERMINED    Ellacoya Locale, Gilford, NH
1.0 mm field of view

Species:           UNDETERMINED
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.0 mm field of view
Field Collected: Tom Mortimer
Catalog No.: u983
Notes:
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UNDETERMINED    Ellacoya Locale, Gilford, NH
0.5 mm crystal

Species:           UNDETERMINED
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 0.5 mm crystal
Field Collected: Tom Mortimer
Catalog No.: u600
Notes:
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UNDETERMINED    Ellacoya Locale, Gilford, NH
1.4 mm field of view

Species:           UNDETERMINED
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 1.4 mm field of view
Field Collected: Tom Mortimer
Catalog No.: u600
Notes: Insert is of a similar appearing peridot crystal, one of my original considerations for these green crystals. But, chemistry does not fit peridot-olivine.
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UNDETERMINED    Ellacoya Locale, Gilford, NH
0.6 mm field of view

Species:           UNDETERMINED
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: 0.6 mm field of view
Field Collected: Tom Mortimer
Catalog No.: u600
Notes: This mineral photos well, so lots of images!
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UNKNOWN    Ellacoya Locale, Gilford, NH
Red-brown bipyramids. 1.5 mm field of view.


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UNKNOWN    Ellacoya Locale, Gilford, NH
Red-brown bipyramids. 1.5 mm field of view.

Species:           UNKNOWN
Locality:          Ellacoya Locale, Gilford, NH
Specimen Size: Red-brown bipyramids. 1.5 mm field of view.
Field Collected: Tom Mortimer
Catalog No.: u631
Notes: May be just pyrite altered to goethite, but something like a pyrochlore group mineral is also a possibility.
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BELKNAP Mts., NH
Summit Piper Mtn.

Locality:          Belknap Mts., NH
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ANORTHITE    Piper-Whiteface Trail, west side Piper Mtn., Gilford, NH
5 cm specimen. Anorthite crystals in diabase matrix
Species:           ANORTHITE
Locality:          Piper-Whiteface Trail, west side Piper Mtn., Gilford, NH
Specimen Size: 5 cm specimen. Anorthite crystals in diabase matrix
Field Collected: Tom Mortimer (Oct., 2010)
Catalog No.:
Notes: Anorthite confirmed by EDS analysis
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ANORTHITE - Labradorite   West side of Piper Mtn., Gilford, NH
5 cm specimen with 8 mm blue-schiller zone of labradorite, top-middle-left

Species:           ANORTHITE - Labradorite
Locality:         West side of Piper Mtn., Gilford, NH
Specimen Size: 5 cm specimen with 8 mm blue-schiller zone of labradorite, top-middle-left
Field Collected: Tom Mortimer - Sept, 2011
Catalog No.: 1804
Notes: This is the first nice blue schiller example of New Hampshire labradorite I have seen.
Labradorite is a member of the plagioglase feldspar series. Labradorite contains 50 to 70 percent anorthite and 30 to 50 percent albite. The host rock is the Gilmantion (Augite) Monzodiorite.
This labradorite fluoresces a deep red color in short wave UV. The glassy-milky labradorite zones are more intense.
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ANORTHITE - Labradorite   West side of Piper Mtn., Gilford, NH
fov 1 cm, blue-schiller zone of labradorite. Zoom view of above specimen.

Species:           ANORTHITE - Labradorite
Locality:         West side of Piper Mtn., Gilford, NH
Specimen Size: fov 1 cm, blue-schiller zone of labradorite. Zoom view of above specimen.
Field Collected: Tom Mortimer - Sept, 2011
Catalog No.: 1804
Notes: Specimen orientation to maximize blue schiller effect. The blue schiller is very dependant on the angle of the incident light.
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FORSTERITE   West side of Piper Mtn., Gilford, NH
1 cm green, glassy, Forsterite bleb in Basalt

Species:           FORSTERITE
Locality:         West side of Piper Mtn., Gilford, NH
Specimen Size: 1 cm green, glassy, Forsterite bleb in Basalt
Field Collected: Tom Mortimer - Sept, 2011
Catalog No.: 1458
Notes: Forsterite confirmed by EDS analysis
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MARIALITE Scapolite group  Lockes Hill, Gilford, NH
3 cm specimen with white embedded prismatic marialite crystals

Species:           MARIALITE - Scapolite group
Locality:         Lockes Hill, Gilford, NH
Specimen Size: 3 cm specimen with white embedded prismatic marialite crystals
Field Collected: Tom Mortimer
Catalog No.: 1488
Notes: Marialite confirmed by EDS analysis. This was a polished grain analysis with a quantitative report. The chemistry indicated by this anlysis is:
(Na2.35Ca1.52K0.23)Al3.95Si9O20.1Cl1.02 , normalized for 9 Si. Clearly a sodium dominant scapolite.
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SILLIMANITE - KYANITE polymorph    Rt 11 road cut, near Minge Cove, Alton
8 cm specimen

Species:           SILLIMANITE - KYANITE polymorph
Locality:          Rt 11 road cut, near Minge Cove, Alton, NH
Specimen Size: 8 cm specimen
Field Collected: Tom Mortimer
Catalog No.: u600
Notes: An aluminum silicate mineral was indicated by EDS analysis. Minerals with this chemistry include sillimanite, kyanite, and andalusite. The hardness tested as 7 to 7.5. This, combined with observed silky-fibrous texture in some areas suggests the species is sillimanite. However other zones within the two specimens collected are more bladed and blueish, suggesting kyanite. Deer, Howie & Zussman state in An Introduction to Rock Forming Minerals that "The polymorphic transition of kyanite to sillimanite appears to be sluggish and local persistance of kyanite in the sillimanite zone of metamorphism is not uncommon." The appearance of this crystal suggests that it was undergoing such a polymorphic transition.
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SYNCHESITE-(Ce)    Rt. 11 storm drain excavation, near Lake Shore Park, Gilford, NH
0.4 mm hexagonal, reddish, zoned, Synchysite-(Ce)

Species:           SYNCHESITE-(Ce)
Locality:          Rt. 11 storm drain excavation, near Lake Shore Park, Gilford, NH
Specimen Size: 0.4 mm hexagonal, reddish, zoned, Synchysite-(Ce)
Field Collected: Clayton Ford
Catalog No.: u954
Notes: Clayton Ford had this specimen labeled as corundum. Synchysite-(ce) indicated by EDS analysis.