👉 The term "felstone" is a medical concept that refers to a specific type of stone, also known as a felspar, which is found in the bone marrow and can be used for various purposes. This term is often associated with the treatment of diseases like leukemia or myeloma, where the presence of this type of stone can indicate an abnormality in the bone marrow. Felsstones are typically small, irregularly shaped stones that may appear on the surface of a person's body