What is a rare Canadian coin?

Inquiring minds want to know, what precisely constitutes a rare Canadian coin? Is it a matter of scarcity, where only a few specimens exist? Or is it the historical significance, representing a pivotal moment in Canadian history? Could it be the artistic value, with intricate designs and intricate craftsmanship? Perhaps it's a combination of all these factors. Could you elaborate on the criteria that define a rare Canadian coin and perhaps share a few notable examples that captivate collectors around the world? Undoubtedly, the subject of rare coins holds immense fascination, and your insights would be greatly appreciated.