You are a gem; you are so precious to me. is this a

idiom

metaphor

personification

simile

onomatopoeia

hyperbole?

Metaphor ...

hyperbole

Explanation:

Hyperbole is the use of exaggeration as a rhetorical device or figure of speech. In rhetoric, it is also sometimes known as auxesis. In poetry and oratory, it emphasizes, evokes strong feelings, and creates strong impressions. As a figure of speech, it is usually not meant to be taken literally.