The peridot dragon is a limited edition gemstone dragon. It is available during the month of August. The most successful way of breeding a peridot dragon is cactus + quartz. This is hinted at in the description of the dragon. It can be bred in the breeding cave or the epic breeding island.
Cactus & Crystal dragon make a peridot dragon
Lava and Mud Dragon
Breed a Crystal dragon with a Cactus dragon.
Either buy it for 1,425 gems or breed it using the cactus dragon and the crystal dragon in the breeding cave.
Peridot
Cactus and crystal i am told
You don't breed a Kairos Dragon in DragonVale. You have to get parts to complete it.
you breed a ice dragon with a mine dragon
You have to breed a plant and a fire dragon.
As of July 2012, there has not been a star dragon in DragonVale.
You have to breed a sun and moon dragon together
You have to breed a metal and a water dragon together.
You have to breed a plasma dragon with a salamander dragon.
Breed the earth dragon with the fire dragon.