The brick moulding process unique to New England is called Water-struck. In this process, very high moisture content surface alluvial clay is pressed into moulds. Water is the lubricant used to release the wet clay from the hardwood moulds. The resultant trowelling effect body as the wet clay slides out leaves behind a textural patina after firing that has never quite been duplicated by any other brick making process.
Locally in New England, because Waterstruck was the most prevalent moulded brick on the scene, the lore of its virtual indestructibility was attributed to its manufacturing process. The reality is that the exceptional durability of this type of brick is due to its superior absorption rate and high compressive strength – both a function of the alluvial clay deposited near the earth’s surface by the recession of the last glaciers at the end of the Ice Age.
Water-struck brick has frequently been mistakenly thought of as a vehicle for designs expressing limited architectural styles such as Colonial, Georgian, Richardsonian, Victorian and sometimes Neo-Tudor or even Neo-Georgian. This view ignores Saarinen’s avant-garde 1955 design of the MIT Chapel with water-struck brick. And, of course, Louis Kahn’s Class of 1945 Library at Phillips Exeter, designed with water-struck brick in the mid-1960s remains to this day an icon of Modern Architecture.
The Proven Durability of Water-struck Brick
Although the exact date of its origin is obscure, it is known to pre-date 1677.
Source: Medford Historical Society, 1989/ Photo Wikipedia.
Test results below indicate why water-struck brick manufacturers for over 300 years
Article from Vermont Brick.