鹿角胶 is made by long-boiling hardened (ossified) deer antler into a gelatinous block, then drying and slicing it. Note the contrast:
鹿茸 (lùróng) is the soft, velvet, un-ossified antler, while
鹿角胶 uses the fully hardened antler. It is classed as a warming tonic in TCM.
