The Silver Cockatiel is a normal gray in dilute form. This mutation has distinct red eyes, a pink beak and pink feet. Male Silvers commonly have a yellow face and orange cheek patches after its first molt. Female Silvers will retain most of the patterns and features of a gray except that it is diluted presenting a silver color.
That is for the general description, a more in depth explanation needs more of your attention.
There are two known types of 'silver' cockatiels. This type of mutation can be acquired from one parent or both, making the single and double factor types. There is also a dominant silver and a recessive silver. The recessive mutation displays a light silvery color, they have red eyes like that of lutinos.
The double factors have lighter plumage than the single factor.
A dark gray cap on a silver bird shows that it is a dominant silver, the only prominent visual difference to a recessive silver aside from the fact that all dominant silvers have dark eyes.
Sexing the silver cockatiel is same as the normal, look for markings under the wing and tail, spots and barring represents a female on mature species.
