What does it mean when someone says " that's the purest thing ever"

"Clean" "uncontaminated" That cat is the purest thing I've ever seen.

At first glance, this statement seems to make little sense, because in the literal sense, something is either pure or it isn't. Pure normally means"not mixed up with any other material," as in "pure gold." However, "pure," according to the Urban Dictionary can also be used informally, to mean "beautiful." So "that's the purest thing ever" could mean, "That's the most beautiful thing I've ever seen."