Ironstone boulder opals are mined in the state of Queensland, Australia. Aboriginals say it is the rainbow that fell from the sky. The old time opal miners of late 1800s and early 1900’s loaded their wheelbarrows with tools and provisions in the town of Charleville. They walked, pushing those barrows,  hundreds of kilometers into the harsh, arid  bush of Queensland to prospect for gem opal. What they found was ironstone and tons of it in many shapes and forms.  Only rarely did they find opal hiding within the ironstone. The iron fist of Mother Nature had to be pried open with sledge hammer, pick, hatchet, or saw before she released her fallen rainbows to the lucky, the clever, the persistent.