Difference between pierce and colpitts

[FreshmanNewbie]

Can someone tell me what's the exact difference between pierce and colpitts oscillator?

I've read in wikipedia that pierce oscillator is the derivative of the colpitts oscillator.

But not sure what is the difference and what advantages we have when we move from colpitts to pierce.

Can someone provide me with an answer on this question.

 

[BradtheRad]

Colpitts traditionally has a transistor providing a 'kick' at some point during each cycle of an LC tank.
Clapp is a variation which adds a capacitor, apparently to assist startup and stability.
Hartley is a variation which has a coupled inductor.

Pierce has a crystal in the place of the LC tank.
Not all crystal oscillators are Pierce type.