More Finds at the Local Antique Shop - Stone Workers?

My husband and I had a fun time conjecturing about this photo and I am interested in hearing your opinions about it. Found in a shop in north central Massachusetts, this image shows men pausing from work to pose as a group. At first, I thought this image depicted blacksmiths in their shop. There are tools similar to those I've seen at local county fairs behind the gentleman on the upper right. At the fair they use them as tongs to hold the metal to be shaped in a fire. My husband noted that a blacksmith would likely wear clothes that are more protective than the cotton aprons most of these men wore. We then supposed that they are perhaps stone cutters. The blocks on the right of the picture may even be big chunks of stone. My husband noted that such men would need to sharpen their tools using the same items as blacksmiths, so I might be correct about the metal tools I first noted. 

Based on past forays into immigrant archives, I know that stone masons were in demand for a wide variety of work in the Massachusetts area. The images I've seen of such laborers show these men at work rather than posed as a group. I think it speaks to the comradery these men must have felt to be photographed in this way. The gentleman so prominently in charge of this group (at the center of the bottom row) likely took great pride in his team and the work that they did. Thinking about immigrant history, I wonder if he helped some of these men get into the country, making note of their special skills and perhaps serving as a sponsor?

This orphan photo leaves me with more questions than answers. Found amongst a pile of rather common portraits, this jumped out at me as unique. Does anyone out there have a collection of related material that may provide more information or that can substantiate or negate my suppositions about these workmen?