Quote Originally Posted by Unregistered View Post
Rough math - 25 AP for the gem quest, average yield is 6300 or so, puts your gems per AP at 252, so you need 39.6 AP per 10k gems
On average, you get half-elixirs at a rate of 1% from the current gemcha, or 1 per every 10k gems spent.
I recorded my last 10 day gemcha and got 67 half elixirs/11000 roll, so I doubt that 1% half elixirs rate is true or it could be my pure bad luck alone.