Meth What's used to add flavoring to meth?

[fettywapo]

I've only smoked the stuff a handful of times, not my thing. But out of the couple times their was green colored big shards that tasted like green apple, and blue ones that was blue raspberry.
Big flavored shards not powder.

What type of flavoring/chemical would be added to the washing/recrystallization process to achieve this?

It's always bothered me and I want to find out lol...