• FavouriteShapes@sh.itjust.works
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        2 months ago

        I think that might be a regional nickname for it - it does indeed form salts which are loosened from the inside of the brick/concrete (both have salts in) by water, and then transported to the outside by the same water.

        • Sylvartas@lemmy.dbzer0.com
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          2 months ago

          I can’t find anything relating saltpeter to the term “evanescence” but I know it forms due to humidity + capillarity in stone/brick walls (I recently moved into a house that has some so I only recently started learning about this) so I guess it is the same thing. The scientific name for it is potassium nitrate