Are the first 7 digits of the Contact ID unique to a CRM Account?

Are the first 7 digits of the Contact ID unique to a CRM Account?

I am looking for a confirmation from someone with this knowledge. It appears that the first 7 characters of the 19-character Contact ID are unique to a CRM account. Am I correct? The 7-digits do not relate in any way to the CRM Account ID so I don't know if this is a valid assumption or not. Thank you.