Although you might have intended to put the code under public domain and thus didn't specify any license, it might still be nicer to mention what license you put your code under. ;)
Copy constructor and assignment operator are flawed. Make the class non-copyable if you don't want copies. But providing copy ctor and op= without implementing them is a bad idea.
You could directly use VertexHolder[I++].texCoords = ...
The == and != operators needn't be friends.
The variables are named inconsistently.
Why not? The static value they are using for float comparison is private, so to my understanding they need to be friends of the class to use it.Ah right, I overlooked that. Let's correct my statement: operator!= needn't be friend. :)