Lichens on rocks - and lanterns
Rocks with lichens growing on them are usually, (I think) very attractive.
But I was astonished to learn today from the Internet that in Britain they have a British Lichen Society.
So I kept looking & on one site, found this paragraph -
Human activities provide many suitable artificial surfaces for lichens, including roofing tiles, cement, asbestos, tarmac and walls of gardens and buildings. Tombs and gravestones in churchyards and cemeteries provide habitats for a good range of lichens."
So, if lichens will grow even on concrete, those of us who have concrete lanterns may - if we live long enough - see the lanterns improve over time.