Coin Grading Explained: Wear, Luster, Strike and the 70-Point Scale

Two coins of the same date and mint can differ in price by a factor of ten or more, and the reason is almost always grade. Grading is the discipline of describing a coin's condition in a consistent way, and once you understand the four things graders look at, published grades stop feeling like a secret code.

The four pillars of grade

• Wear: metal lost from the high points through circulation. It is the single biggest factor separating circulated from uncirculated coins; graders check the highest design points (cheekbones, hair curls, eagle breast feathers) first.
• Luster: the original mint sheen created when metal flows under the dies. Unbroken, cartwheel-like luster is the hallmark of an uncirculated coin, and even light wear breaks it on the high points.
• Strike: how completely the design was impressed. A weakly struck coin shows soft, mushy detail even with no wear at all, which is why weak strike is not the same thing as wear.
• Surface: contact marks, hairlines, scratches, spots and cleaning damage. A harshly cleaned coin can lose most of its collector value regardless of how little wear it shows.

The Sheldon 1-70 scale

Modern grading uses the Sheldon scale, originally devised by Dr. William Sheldon in 1949 for large cents and later adopted market-wide. It runs from 1 (Poor, barely identifiable) to 70 (perfect under 5x magnification). Circulated grades include Good (G-4), Fine (F-12), Very Fine (VF-20 to 35), Extremely Fine (EF or XF-40 to 45) and About Uncirculated (AU-50 to 58). Uncirculated coins, called Mint State, occupy MS-60 through MS-70, where differences come down to luster, strike and the number and location of contact marks rather than wear.

Why grade drives value so strongly

Collector demand concentrates at the top of the scale, and supply thins out dramatically there: far fewer coins survive in MS-65 than in VF-20. The result is that prices often rise gently through the circulated grades and then jump sharply through the Mint State grades. For many series, a single grade point near the top can double the price or more, which is why professional third-party grading exists at all.

Professional grading versus your own assessment

Third-party grading services such as PCGS and NGC authenticate a coin, assign a grade and seal it in a tamper-evident holder. That certification is what the market trusts for expensive coins. For everyday coins, though, paying grading fees rarely makes sense, and learning to assess wear, luster, strike and surface yourself is both practical and satisfying.

This is where an AI assessment can help you triage. Numist photographs the obverse and reverse of your coin and produces a connoisseur-style grading report covering wear, luster, strike and surface. It is an AI assessment rather than a certified grade, so treat it as informational guidance: useful for deciding which coins might justify professional grading, not a substitute for it.

Grading habits that protect value

Never clean a coin to "improve" its grade: cleaning creates hairlines and kills luster, and graders detect it easily. Handle coins by the edge and store them properly so today's grade is still tomorrow's grade; our guide on storing and handling coins covers the details.