Yes, Velvet can be a girl's name.
Velvet is an English given name, and it's primarily used as a feminine name. Its origin comes directly from the name of the fabric, velvet. The name evokes a sense of softness, luxury, and elegance. While not extremely common, it's a recognizable and usable name choice for a girl.
According to Wikipedia's article on the name, it is considered a primarily feminine name deriving directly from the fabric. Velvet (given name) - Wikipedia
Ultimately, choosing a name is a personal decision. Velvet offers a unique and evocative option for parents seeking a distinctive name for their daughter.