Either buy it for 1,425 gems or breed it using the cactus dragon and the crystal dragon in the breeding cave.
Peridot
Breed a Crystal dragon with a Cactus dragon.
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 and crystal i am told
There is no such thing as a Birthstone Dragon on DragonVale
Peridot dragon.... I think I change the time on my phone so it'll think it's 6:40 am then bred a cactus and crystal hoping for one... I read online. I think (and hope) it's a peridot. I've been trying since agust started.... Sometimes u can Only get certain dragons at certain times.:D
As of July 2012, there has not been a star dragon in DragonVale.
You don't breed a Kairos Dragon in DragonVale. You have to get parts to complete it.
To date, there is no grass dragon in DragonVale. You may be thinking of the plant dragon. See the related question.
The incubation time for a rainbow dragon in DragonVale is 48 hours.
Earth dragon and plant drago tip go to eggs and look at the dragon you want and underneath the dragon will be 2 sighns so if it is eart and cold bread them in the right order then you will have that dragon ok bye
Brass Dragon and Fire Dragon