The rarity assigned to each variety is subject to change as more pieces are attributed. I use the most current information available as found in "Copper Quotes by Robinson".
| R-1 |
Common |
R-6- | 25 - 30 Known |
| R-2 | 501 - 1250 Known | R-6 | 19 - 24 Known |
| R-3 | 201 - 500 Known | R-6+ | 13 - 18 Known |
| R-4- | 161 - 200 Known | R-7- | 10 - 12 Known |
| R-4 | 116 - 160 Known | R-7 | 7 - 9 Known |
| R-4+ | 76 - 115 Known | R-7+ | 4 - 6 Known |
| R-5- | 61 - 75 Known | R-8- | 3 Known |
| R-5 | 46 - 60 Known | R-8 | 2 Known |
| R-5+ | 31 - 45 Known | R-8+ | 1 Known |