Play the new version here.
In this build, I added scoring and a losing condition. If you let a gem sit too long, it explodes, ending your game. For scoring, each group that you collect gives you 2^n points, where n is the number of gems in the collection less one. So 1 gem is worth 2^(1-1) = 1; 2 gems are worth 2^(2-1) = 2; 3 are worth 4; 4 are worth 8; etc.
I also added some variations on the sparks, to give you an indication that a gem is about to explode (small blue sparks), and an indication that a gem exploded (big orange sparks).