SILLIMANITE    Gallery                       Return to Sillimanite page.                  Click on image for larger view

Sillimanite is moderately common in the country rocks of the Groton, NH area.
Highslide JS
SILLIMANITE    Draper Hill, Chesterfield, NH
10 cm specimen with prismatic gray-white sillimanite crystals to 1.7 cm

Species:           SILLIMANITE
Locality:          Draper Hill, Chesterfield, NH
Specimen Size: 10 cm specimen with prismatic gray-white sillimanite crystals to 1.7 cm
Field Collected: Tom Mortimer
Catalog No.: 831
Notes:
Highslide JS
SILLIMANITE    Ledge below Palermo #1 Mine, N. Groton, NH
9 cm specimen with cream-colored sillimanite crystals to 4.5 cm in biotite schist.

Species:           SILLIMANITE
Locality:          Ledge below Palermo #1 Mine, N. Groton, NH
Specimen Size: 9 cm specimen with cream-colored sillimanite crystals to 4.5 cm in biotite schist.
Field Collected: Tom Mortimer
Catalog No.: 1460
Notes:
Highslide JS
SILLIMANITE    Ledge below Palermo #1 Mine, N. Groton, NH
Zoom view of specimen 1460 showing splintery structure of sillimanite crystal section. Field of view 1 cm.

Species:           SILLIMANITE
Locality:          Ledge below Palermo #1 Mine, N. Groton, NH
Specimen Size: Zoom view of specimen 1460 showing splintery structure of sillimanite crystal section. Field of view 1 cm.
Field Collected: Tom Mortimer
Catalog No.: 1460
Notes:
Highslide JS
SILLIMANITE    Mine road to Valencia Mine, N. Groton, NH
3.5 cm specimen with white sillimanite crystal sections to 1.3 cm in biotite schist.

Species:           SILLIMANITE
Locality:          Mine road to Valencia Mine, N. Groton, NH
Specimen Size: 3.5 cm specimen with white sillimanite crystal sections to 1.3 cm in biotite schist.
Field Collected: Tom Mortimer
Catalog No.: 1598
Notes:
Highslide JS
SILLIMANITE    Draper Hill, Chesterfield, NH
6 cm specimen with prismatic gray-white sillimanite crystals to 1.4 cm

Species:           SILLIMANITE
Locality:          Draper Hill, Chesterfield, NH
Specimen Size: 6 cm specimen with prismatic gray-white sillimanite crystals to 1.4 cm
Field Collected: Walter Caulkin
Catalog No.: 806
Notes: This is the specimen I acquired from Walter Caulkin at the June 1990 Gilsum Rock Swap. A short time later, Walter guided me to the Chesterfield, NH source locality.
Highslide JS
SILLIMANITE   West side of Piper Mtn., Gilford, NH
5 cm specimen with sillimanite crystals in biotite-garnet schist

Species:           SILLIMANITE
Locality:         West side of Piper Mtn., Gilford, NH
Specimen Size: 5 cm specimen with sillimanite crystals in biotite-garnet schist
Field Collected: Kevin Mortimer - Sept, 2011
Catalog No.: 1800
Notes: Likely from Rangely formation. Hardness tested slightly less than 6.
Highslide JS
SILLIMANITE   Panned from stream on west side of Piper Mtn., Gilford, NH
9 mm sillimanite crystal

Species:           SILLIMANITE
Locality:         Panned from stream on west side of Piper Mtn., Gilford, NH
Specimen Size: 9 mm sillimanite crystal
Field Collected: Tom Mortimer - Sept, 2011
Catalog No.: u1228
Notes: From Rangely formation. Hardness tested slightly less than 6.
Highslide JS
SILLIMANITE   Rt 11 road cut, near Minge Cove, Alton, NH
3 cm partial sillimanite crystal, (upper middle) in 5.5 cm specimen. Matrix is quartz.


Highslide JS
SILLIMANITE   Rt 11 road cut, near Minge Cove, Alton, NH
zoom view of sillimanite crystal.

Species:           SILLIMANITE
Locality:         Rt 11 road cut, near Minge Cove, Alton, NH
Specimen Size: 3 cm partial sillimanite crystal, (upper middle) in 5.5 cm specimen. Matrix is quartz.
Field Collected: Tom Mortimer (2011)
Catalog No.: 1817
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.
Highslide JS
SILLIMANITE-KYANITE   Rt 11 road cut, near Minge Cove, Alton, NH
8 cm specimen with with kyanite-sillimanite crystal zoning. Matrix is biotite gneiss.


Highslide JS
SILLIMANITE   Rt 11 road cut, near Minge Cove, Alton, NH
Zoom view of bottom side shows gray, un-altered sillimanite, top left, blueish kyanite (unfocused) to right. (Green is organic)

Species:           SILLIMANITE-KYANITE
Locality:         Rt 11 road cut, near Minge Cove, Alton, NH
Specimen Size: 8 cm specimen with with kyanite-sillimanite crystal zoning. Matrix is biotite gneiss.
Field Collected: Tom Mortimer (2011)
Catalog No.: 1818
Notes: Zoom view of bottom side shows gray, un-altered sillimanite, top left, blueish kyanite to right.
These Alton specimens are the only examples the author has seen of New Hampshire sillimanite-kyanite zoned crystals.
Highslide JS
SILLIMANITE in biotite-garnet schist    Everet Dam, Weare, NH
6 cm specimen

Species:           SILLIMANITE in biotite-garnet schist
Locality:          Everet Dam, Weare, NH
Specimen Size: 6 cm specimen
Field Collected: Tom Mortimer   
Catalog No.: 1848
Notes: Sillimanite is common in the ledge and rip-rap of the Everet Dam. Collectors unfamiliar with this species should look for lustrous, splintery, gray-white blades embedded in the schist matrix. These blades are difficult to spot in this photo. The sillimanite is the prominent gray-white mineral throughout the specimen.
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