Hardness vs Toughness of Pounamu

Understanding the difference between hardness and toughness is key to appreciating the unique properties of pounamu (nephrite jade). These qualities influence how the stone is worked, worn, and valued.

Hardness (Mohs Scale)

• Definition - Hardness is a material’s resistance to being scratched

• Measured by - The Mohs scale, which ranks minerals from 1 (softest, talc) to 10 (hardest, diamond)

• Pounamu’s Rating - Nephrite jade typically scores 6 to 6.5 on the Mohs scale

• Implication - While pounamu can be scratched by harder materials like quartz or topaz, it still holds up well in daily wear

Toughness

• Definition - Toughness is a material’s ability to absorb energy and resist breaking, chipping, or fracturing

• Not Measured by Mohs - Toughness is a separate property and isn’t part of the Mohs scale

• Pounamu’s Strength - Nephrite jade is exceptionally tough, even more so than many harder minerals. Its interlocking fibrous crystal structure gives it high resistance to breakage

  This toughness makes pounamu ideal for carving, shaping, and enduring impact a key reason it was traditionally used for tools and weapons