Tenacity or Toughness

Tenacity or Toughness of Gemstones

Tenacity or toughness is the ability of a stone to withstand pressure or impact. Minerals which crumble into small pieces or a powder are said to be brittle. If a gem bends but returns to its original position, it is said to be elastic (mica, nephrite, jadeite); these minerals are tough and difficult to break.

The jade gemstones (jadeite, nephrite) are the toughest of all gems, making them also difficult to cut. Talc and gypsum are examples of minerals which are flexible. Ductile or malleable minerals are those (gold, silver, etc.) which may be flattened out into thin sheets under pressure.

The brittleness factor of a gemstone

this is an important consideration in gem cutting and polishing. Many gem crystals shatter or chip easily, and this must be taken into consideration when cutting.