The fact that it phenolphthalein turned pink when it was added to a solution with it in it just makes me think logically that it can't be ammonium chloride. I know we repeated the phenolphthalein test 3 times. Each time it turned pink. I also tested it in the distilled water we were using just to be safe (it stayed clear).
I guess it could have also been possible that the sample was contaminated.
Another sample sublimed when we heated it. We had no other possibilities that sublime (sodium hydrogen carbonate, potassium iodide, starch, sucrose, and calcium oxide were the other possibilities).
When I heated the sample I kept it at the top of the bunsen burner flame, so I'm not thinking it got hot enough to decompose. For the heck of it though once we had finished, I reacted some of the calcium oxide with water to produce calcium hydroxide. I then added that to my suspected ammonium chloride, heated very gently (I made a "camp fire" flame with the bunsen burner for this), and got a reaction. The gas that came off of it smelt like ammonia (I removed it from the flame area so I could check for ammonia, and not have it burn off).
Thanks for your response though Borek.