These two phrases share similar meanings. They both refer to her growing and becoming taller. Alternate translation: "You matured and grew taller" (See: [[rc://en/ta/man/translate/figs-doublet]])
Here the woman, who represents Jerusalem, is spoken of as if she had become the finest of all jewels, that is, as if she had become the most beautiful of all women. (See: [[rc://en/ta/man/translate/figs-metaphor]])
# you became the jewel of jewels
Some modern versions translate "You became old enough to wear jewels."