Is This 1950 Double Die Rare?

it is machine damage

The coins and canada website is not a doubled die either... that website means well, but it originally started off as a French site, and I think some things were not properly translated into proper error coin nomenclature.

Lots of people describe a "doubled die" as anything that isn't a crisp clear strike with no overlapping, failing to realize all of the different reasons for the anomoly. Machine or Mechanical Doubling are "doublings" that are due to mechanical or adjustment processes. A true "doubling" is a physical modification that has been done to the die or matrix, not anything mechanical.

Yeah coins Canada is a great site, but the posters here are right, it's not a doubled die.

You can search around on here and find info about the differences

Here's a good thread
http://goccf.com/t/27811

silver don shared this link on another coin. posted here on the forum. I think this will help a lot. its a very good read.here is the link http://www.error-ref.com/machine-doubling/

I don't entirely agree with the error-ref.com cause, but it gives a couple great photos to show the effect. The latest universal accepted theory/explanation is that the "doubling" occurs just after the downstrike (milli or micro seconds), as the die/press is exiting the planchet .. not on the downward thrust and "slide". As such, it is not really a "striking error" because the strike has been completed but the die has not fully released from the planchet face. The actual "cause" is that the die is loose in its keeper/retainer or that the planchet is loose in its own, causing relative movement between the two. Just tightening things up eliminates the problem. Many books will have quotes from old mint employees talking about it happening and what they did to correct it. I use Alan Herbert's "Mint Errors" reference, a great reference book.