Answer:
Simile is the literary device that was used in the given sentence.
Explanation:
In the given sentence, “Its curves like those of a flower petal” compares the feature of the vase compared to a flower petal which is the characteristic of a simile. Simile and Metaphor compares things to make the reader understand the similarity between the object. The only difference is Simile uses the word “as” or “like” where Metaphor does not. For example, “He is cold as an ice” is a simile and “He is a lion while playing on field” is a metaphor.