What are the rare prime numbers?

Could you please elaborate on what rare prime numbers are? Are they simply prime numbers that are less frequently encountered than others, or do they possess some unique mathematical properties? Are there any specific examples of rare prime numbers that you could share? Additionally, is there a method or formula for identifying rare prime numbers, or is it more of a subjective assessment based on their scarcity? I'm particularly interested in understanding the significance and potential applications of rare prime numbers in the field of cryptocurrency and finance.