Cognomen 柯砚 (柯砚 
) , in all the world, is a very rare surname. The family name 柯砚 is habitual in Eastern Asia, particularly China, where it is an extremely rare surname. More frequently, 柯砚 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 柯砚 | China |