Lapidary medicine is using "stones" as either preventative or curative medicine. "Stones" can refer to a number of different things (it's not a scientific term) such as minerals, gemstones (typically, but not always, minerals), rocks, fossils, and even various types of organic material (coral, pearls, and amber, for example).
I wish crystal healing worked since, as a geologist, I am surrounded by crystals as I sit here typing in my office. Maybe I just need to place them on my head, or perhaps sit on them to energize my root chakra (which would be uncomfortable, especially with the quartz clusters).
Anyway, while lapidary medicine did sometimes work and lead to home remedies still around today, it was often tied up with magical thinking as well (e.g. hematite, or iron oxide, is dark red so it's good for blood problems).
One specific example she mentioned was calamine which is an obsolete mineral name found in lists of inventory in old apothecary shop records. The name comes from a Belgian town (Kelmis) which had a zinc mine and was known by the French as "la Calamine". Geologists don't use the term calamine anymore, it was really a mixture of two two attractive blue-green minerals - smithsonite (ZnCO3) and hemimorphite (Zn4Si2O7(OH)2 • H2O).
She also mentioned pearl juleps. People would drink powdered pearls. She speculated this was for acid reflux since pearls are primarily made of calcium carbonate - the same active ingredient in Tums.
Anyway, I look forward to her book.