Lapiduli appears to be a loose translation of lapideus, meaning, "of the nature of stone." The word makes me think of something organic and natural, but upon further reading, I found a passage written by Richard Baptist O'Brien in 1871 about the life of Catherine McAuley, founder of The Sisters of Mercy (the organization, not the band, although I do like them).
He said "The events of her life are like the lapiduli of a grand mosaic: each of them is a small thing, but the combination of them makes such a picture..."
I'm not very religious, but the idea that we are all part of something larger is exactly the reason I believe that we should value the little things in life. I believe that all contributions are mighty, however small they may be.