What is the value of a 1.3 caret diamond f grade?

The value of anything is worth whatever someone will pay you for it.

The carat weight and colour of the diamond are only two of the four determinants of value: add clarity and cut.

Best practices dictate that you take your diamond to a certified gemologist and pay for a certification of its individual characteristics.

You can purchase such a diamond today on Blue Nile and pay between US$2,879 and US$34,010, depending on the clarity and cut you want.