Granite pegmatite, Alstead field.
References:
Sterrett, Douglas Bovard (1923): Mica deposits of the United States. (USGS Bulletin 740).
Megathlin, G. A. (1928): Spodumene and Autunite from Alstead, New Hampshire (American Mineralogist 13(12):578-579)
Meyers & Stewart (1956): Geology of New Hampshire, Part III.
Mineral List:13 entries listed. 10 valid minerals.
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