When was the last time Diamond Head volcano was active?
150 000 to 200 000 years back
Gemstone Mind is monogenetic meaning eruption occurs just once. The final eruption from the volcanic tuff cone was likely 150 000 to 200 000 years back. It’s continued to be dormant since.
Why is Diamond Head not active?
It had been an energetic volcano previously over 150 000 years back but continues to be dormant since and there’s no lava within the crater. The Gemstone Mind grew to become famous within the 1820’s when crews from British ships discovered calcite crystals around the crater.