Cognomen เพชรน้ำค้าง (Crystal 
, เพชรน้ำค้าง, Petchnamkhaw 
) , in all the world, is a common last name. The family name เพชรน้ำค้าง is characteristic of Myanmar, where it is quite a common surname, Macao, where it is quite a rare surname, and Hong Kong. Measured by absolute frequency, it most frequently occurs in Myanmar, the United States, and Mexico. Much more prevalently, เพชรน้ำค้าง is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Crystal | Hong Kong, Myanmar, Canada, United States, China |
| Petchnamkhaw | Thailand |