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U. S. Route 7 Expressway (Danbury line to Iron Works District), Brookfield, Fairfield Co., Connecticut, USA

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Latitude & Longitude (WGS84): 41° 27' 4'' North , 73° 23' 42'' West
Latitude & Longitude (decimal): 41.4511111111, -73.395
The expressway section of U. S. Route 7 extending from Interstate 84 in Danbury to exit 12 at U. S. Route 202 in Brookfield was constructed between 1974 and 1976. The section from the Danbury/Brookfield line (from just north of the Agstone Co. marble quarry) to exit 12 at U. S. Route 202 (apparently the "Iron Works district" in Brookfield) traverses mostly sediments along the Still River and not much apparent bedrock. One roadcut is visible on the right of the northbound lanes, about 1 mile south of exit 12. However, Januzzi (1976) and (1994) reports a long list of minerals, many repeated in Weber and Sullivan (1995).

In Januzzi (1994) he shows photos of several minerals from the Iron Works district, apparently from exit 12, then the northern terminus of this stretch of expressway (which has since been extended further north), where bedrock evidently was encountered. Clarke (1958) shows outcrops in the area of exit 12, mapped as dolomitic marble of the Inwood (now called Stockbridge) marble, mixed with "younger granite" (now mapped as granite Proterozoic granitic gneiss).

Although the identical list of minerals in Januzzi (1976) and (1994) says all the minerals are from the U. S. Route 7 expressway construction, details accompanying photos in Januzzi (1994) indicate some came from pegmatites in the "Iron Works District", some locations "undisclosed". Because no one else has documented the specific localities and minerals, that information has largely been lost. That is unfortunate because, as Januzzi (1994) states:

The author’s research there not only confirms Shepard’s spodumene discovery in the area in 1835 (Shepard, 1837) but also establishes, in the record, a whole series of minerals that have previously not been reported including chrysoberyl, beryl, beryl var. morganite, triphylite, hydroxyfluorapatite, dickinsonite, bertrandite, as well as a number of common species.

Some small specimens attributed to Brookfield and formerly in the Januzzi collection have turned up.

The coordinates are for the approximate mid-point of this stretch of highway.

Mineral List

69 entries listed. 58 valid minerals.

The above list contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Shepard, Charles U. (1837), A Report on the Geological Survey of Connecticut. Hamlen, New Haven.

Clarke, James W. (1958): The Bedrock Geology of the Danbury Quadrangle. State Geological and Natural History Survey of Connecticut Quadrangle Report No. 7.

Schooner, Richard. (1961), The Mineralogy of Connecticut. Fluorescent House, Branford, Connecticut.

Januzzi, Ronald E. (1976): Mineral Localities of Connecticut and Southeastern New York State. The Mineralogical Press, Danbury, Connecticut: 185.

Januzzi, Ronald E. (1994), Mineral Data Book - Western Connecticut and Environs. The Mineralogical Press, Danbury, Connecticut.

Weber, Marcelle H. and Earle C. Sullivan. (1995): Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70(6): 397.

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