Granite rolls

The uranium that is found in roll-front deposits is generally believed to be derived from the dissolution and leaching of host minerals by soil water and ground water (2 3). Typical source rocks for the uranium are granites, tuffs, and tuffaceous sandstones that have relatively high concentrations of uranium in... 

The first American paint factory was opened in Boston in 1737 by Thomas Childs (2). The pigment and oil were placed on a granite trough, and a granite ball, known as the Boston Stone, was then rolled over the mixture to make the paint. The ball is now preserved and serves as the symbol for the Federation of Societies for Paint Technology. 

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