Final answer:
The rhetorical device in the sentence provided is alliteration, which involves the repetition of the initial consonant sound in closely located words to create an effect.
Step-by-step explanation:
The rhetorical device being used in the sentence 'I broke the locket with a thick brick' can be interpreted as an example of alliteration. Alliteration is the repetition of the same initial consonant sound in closely situated words. The repetition of the 'b' sound in 'broke', 'brick', and 'thick' is what makes this sentence an example of alliteration.
Rhetorical devices are tools that authors use to persuade or convey their points more effectively. Alliteration is just one of many rhetorical devices that can be employed in language to create a memorable or impactful effect. When analyzing literature, one can also look for other rhetorical devices such as repetition, similes, metaphors, parallel structure, and personification.