White X On Orange Field

I have about 3 pages of loose stamps that need sorting and, while going through the US 'Revenue' stamps, I came across this. No notation(s), no ID, nothing. Any ideas, thoughts or suggestions would be appreciated.

Sometimes sheets of stamps have designs on the selvage outside the printed stamps on the sheet - this may be a sheet selvage design.

orstampman - Thank you. Finally something to look up. I saw it there and thought 'what the heck ...'. Then I sat and thought about it for a while and got to thinking it might be something associated with the military - some destination designation or what not from WWII. Then got to thinking .... Figured I'd try this category. Thank you for the response.

That looks a lot like a Dutch booklet "stamp". If a booklet had a certain amount of postage in it, like let's say 1 Euro ( or guilder ) and room on the sheetlet was left, a cross was printed on that position. The only crosses like it I have seen though were red on white, never the other way around! But it is possible that there are reversals!
I stick with the booklet "stamp" because of it's one imperforate side.

Peter

As Peter has already mentioned, it is most likely from a booklet and would have looked something like this originally. Someone might have the identity of the country but as it is not attached to a "proper" stamp it cannot be said to be worth anything but it is interesting anyway.

Not from a booklet at all.

It is a space holder stamp from Austria 1858 issue 5kr red "Saint Andrews Cross" - identical to Lombardy Venetia 5 sold red also.

Great information! As in this example (taken from the alphabetilately.org website):

They do have a value even as singles. Attached to stamps they are mucho rare. My ancient Gibbons Austria lists this as £25 with gum, yours is unfortunately not in the best condition but still worth keeping

One and all - Thank you! Just now read about the cross - had to go out and troubleshoot a 'puter. One of the reasons I do like this forum. There is such a wealth of knowledge. I have no idea what will be done with it, but now I can tell them just what it is. Maybe even find something in red/orange and white. Again, thank you for the effort and information.