Old lead mine, Brookfield, Fairfield County, Connecticut, USAi

Regional Level Types
Old lead mine	Mine (Built Over)
Brookfield	- not defined -
Fairfield County	County
Connecticut	State
USA	Country

A very old lead mine now covered by an industrial building on the south side of Silvermine Road just west of the US Route 7 expressway. Januzzi (1976 and 1994) claims it is the country's oldest, but provides no evidence for this. It is a rather obscure place that does not appear in any collecting guidebooks and that Schairer (1931) noted "Produced some very interesting minerals at one time. The locality is now overgrown and difficult to find. Galena and sphalerite in limestone may still be found there." The only real description comes from Shepard (1837):



It did not pan out and is only briefly mentioned in Pulsifer (1888):



All subsequent writers essentially paraphrase Shepard or list the minerals he notes from there. However, Shepard's use of the term "calamine" lead to confusion between smithsonite and hemimorphite by subsequent writers like Schrader, Stone and Sanford (1917), Schairer (1931), Januzzi (1959) and Schooner (1961) who call it hemimorphite. However, a full reading of Shepard (1837) reveals this passage:



Elsewhere he describes it as "in the state of an impalpable powder of a white color, and in cellular, bone-like masses accompanies the blende and galena of Brookfield" and "Pulverulent; white. Associated with blende and calcareous spar."

On the other hand he discusses what is now called hemimorphite as “electric calamine” and mentions its occurrence in the local iron blast furnace chimneys, but not at the Brookfield mine. He notes its silica and water content, which clearly distinguishes it from smithsonite.

Also potentially confusing is his term "white lead ore", which could be anglesite or cerussite, but considering that the ore is hosted in marble, the latter seems most likely. He says it was "noticed only in a few small crystals".

Yet somehow Schairer (1931) transmogrified this into his entry for "calamine (hemimorphite) Found in good crystals formerly at the old lead mine southeast of Brookfield." None of which is correct according to Shepard (1837). Thus Januzzi (1959) paraphrased it to "Hemimorphite has been found, in the past, as crystals of fair quality at the old lead mine, southeast of Brookfield." And similarly Schooner (1961): "This mineral came from the old lead mine in Brookfield, in rather good specimens" though he admits "the author has seen none of the material" and according to Shepard (1837) he never would have!

The only new information since Shepard (1837) comes from Januzzi (1994) as a result of the Brookfield bypass section of the U. S. Route 7 expressway construction:



Based on a photo in Januzzi (1994), the "greenockite" is little more than thin yellow-green coatings, which appear similar to Shepard's (1837) pyromorphite description as "Pulverulent. Yellowish green". So which mineral is it? Analyses appear necessary.

Specimens recovered around Route 7 construction time consist of brecciated matrix (the ore body is clearly a brittle fault zone, one of many similar ones in western Connecticut) rich in talc from hydrothermal alteration, with disseminated veinlets of calcite, galena, sphalerite and pyrite with yellowish, supposed greenockite coatings.

Other Regions, Features and Areas containing this locality

References