Many of you may have seen coins listed on ebay refered to as R-2 or R-6 etc......but what does this really mean?

below is a list of the (R) RARITY SCALE:

R-1 Common
R-2 Not So Common
R-3 Scarce
R-4 Very Scarce (population est. at 76-200)
R-5 Rare (31-75)
R-6 Very Rare (13-30)
R-7 Extremely rare (4-12)
R-8 Unique or Nearly So (1, 2 or 3)

You can verify if a seller is giving you the real (R), or if you're a seller, you can look-up the (R) of your coin by visiting 'www.coinfacts.com'