hmmm sounds to me like whoever was growing that weed was growing it in a metal bucket or something similair like a galvanized tub or something. One of my buddies had this happen and he was the one growing it so he was able to find out what caused it.

its almost like iron or zinc or something is in the bud to make it crackle and sparkle

oh damn or what choppile420 said because i have had that happen too if you light the lighter right above the bowl some flint flys out and sparks and bounces around and the first time it happened i thought it was because of the weed but it was just me being a dumbass