I love old diamond frames. That looks like a fairly early one compared to what we usually find. It looks like it has a closed front fork, which goes back a ways. How are the joints between the pipes made? Are they the old style where one tube was folded open inside the other? Mr. Columbia is right about the silhouette. It kind of looks like a Columbia at first, but then when you really look at it, it looks like something else. It's a nice find either way.