Does anyone have any clue or theory about how to get specific shards besides using the balloon popping game? I need magic shards but all I get are laughter shards... Those parasprites are all purple in my ponyville and I have no magic shards to retaliate with!
Bears, Beats, Battlestar Galactica...... --Dwight Schrute(Jim Halpert) "THE OFFICE" FOREVER
Just keep making / selling stuff, other ones will pop up eventually and rarely. I find with the quicker items, laughter shards are common, but with things that take more time, you'll get different ones.
My theory is that shards of a particular element become more common once you've unlocked the corresponding stone on the map. Unfortunately, I can't really test this out yet as I need 75 shards for generosity and I only have 9 so far. >_<