Understanding the MOHs Hardness Scale: A Guide for Diamond Buyers

Understanding the durability and hardness of gemstones is crucial for every diamond buyer. The MOHs hardness scale is a vital tool in this process, helping to determine a gemstone's resistance to scratching. In this blog, we will delve into the MOHs hardness scale, compare various gemstones, and highlight why diamonds are considered the most durable choice.

What is the MOHs Hardness Scale?

The MOHs hardness scale is a crucial tool in the world of gemology, measuring the scratch resistance of various minerals. Developed in 1812 by Friedrich Mohs, a German mineralogist, this scale helps to classify minerals based on their ability to withstand scratches from other substances.

How the Scale Works

The MOHs hardness scale ranks minerals on a scale from 1 to 10, with 1 being the softest and 10 being the hardest. Each mineral on the scale can scratch those below it and be scratched by those above it. The hardness of a mineral is determined through a scratch test, where the ability of one mineral to visibly scratch another is observed.

  • 1 - Talc: The softest mineral, easily scratched by all others.
  • 2 - Gypsum: Slightly harder than talc but still very soft.
  • 3 - Calcite: Can be scratched by most metals and harder minerals.
  • 4 - Fluorite: Harder than calcite but softer than most other gemstones.
  • 5 - Apatite: Represents the middle of the scale.
  • 6 - Orthoclase Feldspar: Hard enough to scratch glass.
  • 7 - Quartz: Common in everyday materials, quite durable.
  • 8 - Topaz: Much harder than quartz, used in various jewelry.
  • 9 - Corundum: Includes sapphires and rubies, extremely hard.
  • 10 - Diamond: The hardest known material, unrivaled in durability.

Comparison of Gemstones on the MOHs Hardness Scale


MOHs Hardness Rating


Recommended Use



Extremely resistant to scratches, maintains brilliance and polish

Ideal for all types of jewelry, especially daily wear items like engagement rings



Highly durable, resistant to scratches, excellent diamond alternative

Suitable for engagement rings, earrings, and fine jewelry



Highly durable but can be scratched by harder materials

Perfect for rings, bracelets, and other jewelry items



More prone to scratches and chips, requires careful wear

Better suited for occasional wear pieces

Cubic Zirconia (CZ)


Relatively hard but can scratch and lose brilliance over time

Ideal for fashion jewelry, not recommended for everyday wear

Key Factors to Consider When Choosing a Gemstone Based on Hardness

When selecting a gemstone, the MOHs hardness scale is essential for making an informed decision. Here are the key factors to consider:

Daily Wear vs. Occasional Wear

  • Daily Wear: Choose harder gemstones (9-10) like diamonds and moissanite for items worn frequently, as they resist scratches better.
  • Occasional Wear: Softer gemstones (7-8) like emeralds and CZ are suitable for less frequently worn pieces.

Lifestyle and Activity Level

  • Active Lifestyle: Opt for durable gemstones like diamonds and sapphires.
  • Less Active Lifestyle: More flexibility, but consider the potential for scratches.

Care and Maintenance

  • Ease of Maintenance: Harder gemstones require less frequent care.
  • Special Care Requirements: Softer gemstones need more careful handling and regular maintenance.

Investment and Longevity

  • Long-Term Investment: Harder gemstones retain value and last longer.
  • Short-Term Use: Softer gemstones are cost-effective for fashion jewelry but may not last as long.

By considering these factors, you can choose a gemstone that suits your lifestyle and ensures lasting beauty and durability. Rest assured your House of Quadri lab diamond has the highest durability and will stand the test of time.