Normal Grey - the "wild" coloration of cockatiels. The most common mutation available. It consists of a grey cockatiel with white wing tips and orange cheek patches. Upon maturation, the males obtain a bright yellow face, while the females retain their dull grey face, often with a small glint of yellow.
Pearl - A patterning of yellow dots all over the bird, excepting the head, which is a bright yellow with orange cheek patches. Males will lose most or all of their pearling upon maturation, and look very similar to normal grey males. Females retain the pearling.
Cinnamon - very similar to normal grey, these birds are a brownish color rather than grey.
Lutino - these birds can either be completely yellow with orange cheek patches, or posess yellow heads with orange cheek patches and white bodies. They have red eyes and pale beak. Lutinos can be seen frequently at pet stores with bald heads, this is a result of poor breeding. They are impossible to visually sex.
Yellowcheek - again, similar to to normal greys, except with yellow cheek patches.
Pied - a bird that looks like a washed out normal grey - it has a yellow body with grey patches, preferably symmetrical. They can have yellow heads, though a patch may cover it. They are impossible to visually sex.
Whiteface - this mutation replaces all yellow and orange pigment with white. Thus, a male whiteface will gain a whiteface upon maturation and has no cheekpatches.
Fallow - a fallow is even lighter than a cinnamon, with red eyes, pale claws and beak.
Silver - silvers are again similar to normal greys, but have silvery feathers instead of the dark grey. They also posess red eyes, pale claws and beak.
Pastelface - similar to Yellowcheek, with the yellow cheek patches, but is not a sex-linked trait like Yellowcheek.
Albino - they aren't real albinos, they are merely a combination of whiteface and lutino. They are all white birds, with pale feet and beak, and pinkish eyes.