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New 100-point coin grading scale proposed

Ever find yourself wishing for more coin grades to learn?

If you have, Ron Guth is the numismatic authority for you.

He has created the Guth 100 Point Coin Grading ScaleSM.

There are 20 more points added to Mint State and proof grades.

“The new system complements and integrates the old 70 point system, leaving the grades below 60 intact,” said Guth.

Before you dismiss this idea out of hand, consider his stellar numismatic background.

Guth is a former President of Professional Coin Grading Service and

PCGS was the first mover in establishing commercial third-party coin grading back in 1986 and encapsulating coins in plastic slabs.

That idea took off, and the hobby has never been the same since.

Why do we need an expanded grading scale?

“The rare coin market has used a 70-point system developed in 1948 by Dr. William Sheldon, originally for use with U.S. large cents minted from 1792 to 1814. In the 70 years since the Sheldon scale was developed, coin grading has changed dramatically. Converting to a 100 point system is a logical and necessary next step,” Guth said.

This history is true.

When the American Numismatic Association adopted numerical grading in the 1970s, it simply took the Sheldon scale and applied it to all coins.

In a decimal and metric world, 70-point scales are clunky.

Don’t forget that third-party grading services are expanding around the world.

It is not just American sensibilities in play.

To explain why we need 20 grading points on Mint State and proof coins, Guth said this:

“Currently, the coin market squeezes plus or half grades, known as split grades, into the 60 to 70 range. The Guth 100 Point Coin Grading ScaleSM assigns whole numbers to split grades and eliminates decimals, rounding and pluses,” said Guth.

That is true – today.

Those who remember the evolution of coin grading can recall when all the numerals were not used.

We had -60, -63, -65 and -67. That was it.

There were even those who once believed that -70 would never be used because it indicated perfection.

I wonder what those people presently make of the modern coin market and its regular assignment of the -70 grade.

Will these modern issues now make MS-100, or fall short at MS-98 or 99?

There have been trial balloons floated before relating to a 100-point grading scale.

Up to now, those trial balloons just floated away unnoticed or were shot down.

What will happen this time?

Guth is widely respected in the industry.

The modern coin market probably needs the next big thing to accelerate sales.

With Chinese buyers becoming more and more important, adopting a new 100-point scale might appeal to them more than the old American 70-point system.

What happens next becomes a matter of willingness to change among coin collectors.

For third-party graders, this is solid gold.

Every coin that is presently slabbed will need regrading – for a fee.

Money makes the world go around.

If you want to check out the details, and see a chart mapping the Sheldon 70 point scale to The Guth 100 Point Coin Grading ScaleSM, go to

And speaking of money, for licensing opportunities, contact Guth at Expert Numismatic Services, Inc. at 858-349-8270, or

If the line is busy, try again. That might be me who got in ahead of you.

Buzz blogger Dave Harper won the Numismatic Literary Guild Award for Best Blog for the third time in 2017. He is editor of the weekly newspaper "Numismatic News."