Horn and bone are both materials that have been used in jewelry for millennia. They can be very beautiful materials but make sure to check that surface finish because both horn and bone can be quite porous. A good finish is essential.
Since this material comes from animals, it is also important to check its origin. Unfortunately, it is still too common that materials are offered that have been obtained in an unethical manner and that bring unnecessary pressure and suffering to nature. Suppliers who cannot prove the origin of the material they sell should be avoided.