First two frames show the sand tit as hangs from ironstone seam band. Last frame is of a sandtit that has been contour plished and cut into an opal stone. Arrows show the opalized split of the tit away from the ironstone biscuit band seam.

Sand tits form attached to an ironstone biscuit band. The biscuit band is a seam of ironstone  laying in the sandstone and clay levels. The ironstone sometimes has opal lines and pools within it.
The brown ferruginous sandstone formations look like little miniature stalactites hanging from an ironstone biscuit band in clay. The sand tits’ ironstone has a more sandy consistency than do the  hard ironstone nuts. And the tits have a yellow ochre, thin limonite colored exterior skin. There can be more horizontal lines of opal in a tit besides at the join to the ironstone band. One theory is that this formation is the result of annelids that are little wormlike, segmented creatures that bored into the clay bed of ancient sandy sea floors. Most must be contour cut with a dremil tool in order to cut into stones.

Santa Fe jewelry designer, Janelle Benton, put together this setup of stones as an earrings design. It typifies the versatillity of Yowah and Koroit Boulder opal matrix stones. You can see why Yowah and Koroit opal have earned the title Inspiration Stone.

Sometimes the opal and ironstone combine in a way that looks like an object, a landscape, or a lifeform. This half of a Yowah nut looks like a penguin. Picture stones like this are collectible and most miners have one or two sitting on the shelf in their mining hut. This one is the size of my palm and has another half nut that matches it. There is no fire showing in the opal. So the opal that makes up the figure is called “potch” or “common opal”. This piece is still in the rough and has not been polished. I sawed two thousand Yowah nuts (yes, I counted them) and found only two picture stones.

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.