The Mohs Scale

19 February 2019 / Blog

What is the Mohs Scale?

The Mohs scale is a measures the relative hardness of natural materials, which are ranked on a scale of 1 to 10, with 10 being the hardest possible substance. Diamonds, get a natural 10 on the scale.

  1. Talc
  2. Gypsum
  3. Calcite
  4. Fluorite
  5. Apatite
  6. Feldspar
  7. Quartz
  8. Topaz
  9. Corundum, ruby, sapphire
  10. Diamonds

Numbers are assigned based upon a simple test: when two substances are rubbed together, the substance which scratches is assigned a lower number. The Mohs scale itself is interesting: it was invented in 1812 by a German geologist named Friedrich Mohs, but similar methodologies had been used for millennia: Pliny the elder, a Roman philosopher from the 1st century C.E. mentions a similar process in his work Naturalis Historia. Although the methodology of the Mohs scale may seem primitive, it is still widely used by geologists to this very day.

mohs scale for diamonds

The AGS Diamond Grading System

Every diamond graded by the AGS is analyzed for its color, clarity, and cut by at least two gemologists. Carat weight and proportions are measured using carefully calibrated computerized instruments. The AGS uses a unique numerical grading system to quantify diamond color, clarity, and cut. A grade of 0 indicates the rarest, most valuable quality, while a rating of 10 is the least desirable.

Blog archive


Our consultants understand the emotional weight of making this important decision. To guide you through the process and help you create your never ending bond, please talk to us.
Subscribe to our newsletter
Track your order