A steel mixer may sit on the counter while a small stone mortar remains within reach. The question is not which tool is more authentic. Ask what the cook reaches for when only two cardamom pods need breaking and what they use when preparing food for twenty.
In a museum or family collection, examine the working surfaces. A hollow polished smooth, a heavy base and a pestle comfortable in one hand tell you about repeated movement. They do not tell you exactly what was ground. A label that calls an object a medicine grinder needs a provenance stronger than its resemblance to a picture.
Record who used the tool, where it was kept and whether food and medicinal materials were handled separately. Do not put an unknown residue back into food use. The most revealing answer may be an ordinary one: the tool stayed because it was quiet enough to use before the rest of the house woke.
Further reading: Ayurvedic medicine: evidence and safety (NCCIH)