I know quite a bit about crack.
1. It was used for crack. But everyone has come to that conclusion as well.
2. did one end have tape or something else on it to stop them from burning their mouths while smoking it? If so, it was DEFINITELY a crack pipe.
3. Did one end have chore boy in it? If you find a product call chore boy lying around, he was DEFINITELY smoking crack. They put it in the pipe as a filter when they smoke the rock.
4. Crack, like others have mentioned, is a white/yellow color. It looks like plaque to me, lol. I don't know what it smells like, but it should be a bit soft or crumbly.
5. Sometimes they will cook the cocaine themselves on a spoon, so if you see your spoons disappearing, then he again, is DEFINITELY smoking crack.
6. Crack highs don't last very long, so generally a smoker has to do it quite often, so they will light up anywhere pretty much. They usually have really blood shot eyes, but not like with smoking weed. They aren't relaxed after smoking it since it makes them jittery. Since he is lying about it, he will be trying to act normal but you'll be able to tell something is wrong.
7. When they have the crack on them, and its a small amount, they usually keep it in their hand. So if his hand is always in his pocket or he is walking around with something small in his fist, its probably some crack. They dont want to lose it so they keep a close eye on it.
8. I know that cocaine is cut with baking soda and cooked to form crack, so if you find a pot with water in it, and a jar with white residue and some baking soda in your kitchen well..he was cooking crack. I think crack has a sweet smell when its cooking, though I can't remember.
9. Crack pipes are called "stems" and they look differently from bongs (for weed) and pipes used for meth. They are usually cylinders with small diameters. I've seen antennas broken up and used as crack pipes. A corner store in my neighborhood used to sell "ink pens" and when you took all the pieces apart, you'd have a glass stem left to smoke crack from since its illegal to sell the pipes alone. Generally the diameter is no bigger than a centimeter, but might be a little bigger.
10. Some crack is sold in vials, but I've seen it mostly done it baggys. Not the kind they use for dime bags of weed either. Generally crack is portioned off into small corners of plastic and the plastic is twisted and ripped off and then burned to keep the crack inside. So if you find bits of plastic around...yea he is smoking crack.
11. Look at his index and thumb on both hands and his lips. Are they burned or browned from holding a hot pipe?
12. When a person smokes too much crack they can sometimes get really sick and start throwing up even if they haven't eaten anything. He will probably try to hide the sickness so you don't expect anything. Don't let it slide.
Verdict:
I say get rid of his ass. One thing that I've learned is that you can't trust a crack head. they will do anything to get the drug. They have no shame after a while. They will lie, steal, cheat, and hurt anyone who gets in their way with no remorse. I know you probably feel bad for him, but you can't save someone that doesn't want to be saved. Its really hard for people to get off of drugs like crack and I've seen people addicted to the shit for decades. I've seen people lose literally everything over it. They will stoop to the lowest of levels for crack. It aint worth it man. Wash your hands of this situation before you get screwed over. Don't wait until you come home and some of your stuff is missing because he sold it and skipped out on you. Refer him to a rehab or something.