I have an "unbreakable" glass spoon that I bought from a custom glass blower. They are breakable, but you need a lot of effort to break one. He was telling me a story of one of his customers pieces that he made, and his customer got pulled over by the police. They found the pipe, and he was told the cop chucked the pipe to the ground several times and it wouldn't smash. He tired breaking it in half across the cemet and his car, no breaking. It took a hard kick from the officers boots to break the pipe, and it didn't shatter, it just snapped in half. VERY tough glass.

The first glass pipe i ever bought, like 5 yrs ago, the guy at the counter did the same thing as you. He took it, and beat it against the counter really hard. Didn't even crack, so I told him give me a different one and I'll buy it.