Interstate 290/Interstate 495 interchange road cuts
Marlborough, Middlesex County, Massachusetts, USA
Key Information
Do not enter mining areas without proper authorization.
The Interstate 290/Interstate 495 interchange road cuts in Marlborough, Massachusetts, are a notable mineral locality with a variety of collectible minerals.
Research suggests the area features metamorphic rocks like gneiss and marble, exposed during highway construction in the 1970s.
It seems likely that the site is popular for mineral collecting, with no traditional mining history but active since at least the 1970s.
The evidence leans toward a humid continental climate, with warm summers and cold, snowy winters, supporting diverse local ecology.
Geographic Location
Located in Marlborough, Middlesex County, Massachusetts, about 30 miles west of Boston, this site is at the busy interchange of Interstate 290 and Interstate 495. Nearby towns include Hudson, Berlin, Northborough, and Bolton, each within a few kilometers, offering additional attractions for visitors.
Minerals and Geology
The road cuts reveal a rich array of minerals, including quartz (notably smoky quartz), actinolite, albite, allanite, almandine, and rarer finds like autunite and molybdenite, appealing to collectors. The geological structure consists of metamorphic rocks, such as gneiss, calc-silicate rocks, and marble, exposed during construction phases in 1970, 1973, and 1980, reflecting New England's complex geological history.
History and Culture
While there’s no traditional mining, the site has been a collecting hotspot since at least the 1970s, with local mineral clubs like the Worcester Mineral Club (21 km away) fostering community interest. Marlborough, with a population of around 39,818, has a deep historical background, including 17th-century Native American interactions, and features parks and the Assabet River for recreation.
Climate and Ecology
Marlborough experiences a humid continental climate, with summers averaging highs of 82°F in July and winters dropping to lows of 20°F in January, with significant snowfall from November to April. The Assabet River and lakes like Lake Williams support a diverse ecosystem, including wetlands and deciduous forests, enhancing the area's natural appeal.