Plainfield rhodonite

The USGS record for the Betts Manganese Mines, also known as the Taconic Manganese Mine, sits 1.2 miles east-northeast of West Cummington in Hampshire County. Manganese was the primary commodity, iron second, and gemstone third, which is the whole story of the place in three words: an industrial working whose ore happened to be beautiful.

The material list is why collectors come. Rhodonite and rhodochrosite are both logged here, along with pyrolusite, ankerite and cummingtonite, an amphibole that carries the neighbouring town's name. The rock was worked over by regional metamorphism, and the deposit sits on the east limb of the Berkshire Anticlinorium with local drag folds through it. The ore bodies are lenses striking about twenty degrees east of north and dipping steeply, some 192 metres long and 30 wide.

The field note attached to the record is worth reading as history. A USGS reporter in September 1971 described the gem-quality rhodochrosite as a vein four to six feet wide at the base of the quarry's back wall, behind the flooded section, reachable by climbing fifteen feet down a sheer face, and warned that the vein is highly resistant and needs a heavy sledge and a sharp carbon steel chisel. The same note records the mine as open for a two dollar fee. That was four decades ago. Treat every part of it as a description of the past, and find out what the current arrangement is before going anywhere near a flooded quarry.

A later comment in the same file, dated September 1981, records that rhodonite had just been made a Massachusetts state mineral.

Plainfield itself is the youngest town in Hampshire County, settled in 1770, made a district within Cummington in 1785 and a town in its own right on 15 June 1807. Fewer than seven hundred people live there.

The historic workings are small and on PRIVATE ground; the practical way to get Massachusetts rhodonite is through the Berkshire rock shops and the regional mineral clubs, several of which run field trips.