Nothing but glass

I thought I bought my girl a diamond ring but it turned out to be nothing but glass.
When she had it appraised, she dumped me and then she broke her foot off in my ass.
I should've been suspicious when I saw that the jeweler had his store in a van.
When I told my friends, they said that I'm a very stupid man.
When it comes to having brains, I guess I'm all out of luck.
I should've known that I couldn't get a diamond ring for twenty-five bucks.