Ammonium Dichromate

Orange, crystalline powder that is a classic volcano demonstration.  The powder is piled on an inverted pie tin and ignited with either a match or a lighter.  Turns the lights out once it gets going and you will see sparks flying off the pile and a huge pile of greenish-olive colored ash is produced.  The kids love it.  Because it is a chromic 6 compound it can be very poisonous, especially to small children, in small quantities.  Use appropriate safety measures.