This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 粶 is uncertain. It visually combines 米 (rice) with 录, but the original semantic and phonetic roles are unclear.
Since the meaning is unclear, picture a rare grain of rice (米) next to a mysterious component (录) that looks like a record or a green sprout. The kanji might relate to a specific type of rice, but it remains obscure.
For ロク, imagine a rare grain of rice that looks like a tiny rock: rock -> ロク, and the rice is as hard as a stone.