This could also go over to the classic grading forum I suppose. I had posted a while back about the way I learned about coin grading. Below is what I recently found (close, but not exact as a formula that I have somewhere from years gone by) I cannot find the original paper. I do not work for a
TPG etc. so not even sure if this is used today or not or even if it was ever used. It relates to mint state coins.
Determining Grade
Use the following formula, once you have assigned a numerical grade to the surface preservation, strike, lustre and eye-appeal of each side of a coin:
OBVERSE:
Surface Preservation (1-5) ____________ x2 = ______________
Strike (1-5) = ______________
Lustre (1-5) = ______________
Eye-appeal (1-5) = ______________
OBVERSE TOTAL: ______________
REVERSE:
Surface Preservation (1-5) ____________x2 = ______________
Strike (1-5) = ______________
Lustre (1-5) = ______________
Eye-appeal (1-5) = ______________
REVERSE TOTAL: ______________
Now we relate the following totals to corresponding grades:
5 to 12.99 = MS or Proof-60
13 to 13.99 = MS or Proof-61
14 to 17.49 = MS or Proof-62
17.5 to 18.99 = MS or Proof-63
19 to 20.49 = MS or Proof-64
20.5 to 21.99 = MS or Proof-65
22 to 22.99 = MS or Proof-66
23 to 23.99 = MS or Proof-67
24 to 24.49 = MS or Proof-68
24.5 to 24.99 = MS or Proof-69
25 = MS or Proof-70
For example, a proof coin with an 18 obverse and a 21 reverse could be graded Proof-63/65. However, its overall grading would be Proof-63 since a coin's grade is largely determined by its worst side.
Still, usually the obverse of a coin is considered more important than the reverse. The consensus today is that the value of a coin is determined approximately 60/40 obverse to reverse. In other words, the obverse is about 11/2 times more important than the reverse. Practically the only exception occurs in the case of certain commemorative coins and patterns. In these cases, it is somewhat ambiguous which side is the obverse. Both sides are of approximately equal importance in these instances.
For this reason, it may sometimes be considered permissible to upgrade the reverse grade a bit if the obverse is toward the upper end of the scale of its grade. For example, a coin with a 20 obverse and an 18.9 reverse might still be graded MS-64. However, a coin with an 18.9 obverse and a 20 reverse (a far more common occurrence) must always be graded MS-63.
Whoops, so much for microsoft word :) copy and paste.
You can fix it up a little. Being french I prefer Lustre
to luster. :)
Posted 05/22/2011 4:49 pm
