A view of Yowah where Barbara mines.

Yowah is a geographical location in Queensland, Australia within the ironstone boulder opal country. The "material" mined there can be: Yowah nuts, boulder opal, boulder matrix seams and nodules, pipe opal, opalized wood, and a sandstone opal, also ironstone fossil casts. All these come from the Yowah field. Remember too that "nuts," a concretionary form of Boulder opal, can be found in other areas. The Yowah area is better known because of the quantity found there. Realize also that an area known as Koroit, an hour out of Cunnamulla, (Yowah is two hours out and in a slightly different direction), produces beautiful boulder opal and "nuts" that has often in the past been sold as Yowah nuts. Yowah Nut Opal has gone, it seems, the path of JELLO in becoming the generic term for a gelatin dessert and stands for the ironstone skinned, opal-centered, opal-rivuleted, matrix concretion.

150 gm Yohwah nut with top chipped off. 55mm x 25mm x 47mm depth. Courtesy of Cranestone Gems

Since the Yowah nut has become more and more popular along with Hollywood notables' acquisition of boulder opal, and the widespread demand by jewelers and artisans for more of the Queen of Gems, there has been a rush by many dealers to have some on hand for sale. Consequently the chances of making some very good buys by the knowledgeable and lucky from the not so informed seller are pretty good. The downside is that neither you nor the vendor has x-ray vision. The ironstone nut can contain a lovely gem, mud, sandstone, ironstone, or air. Even broken chunks, and they nearly always are broken open, can contain hidden rivulets of fire in an ugly plain brown rock.

Opalised Wood from the Black Gate Opal Field at Yowah. The color came from a section a foot long, but this was the best piece. Currently in a private collection. Courtesy of Cranestone Gems

To learn about Yowah rough, you have to look, then cut hundreds of times on many pieces of rough. Once the cut or rub has been made, go back to looking at the outside surface of the nut to see what clues were there indicating the possibility of what you learned about the interior prior to opening the material. I can only give you a few indicators here:

GLUG - a peach or orange colored potch
LEATHERY look to outside skin
OPAL color, rivulet, or twinkle
JUICY look of shiny potch in skin
HEFTY weight, empty nuts are lighter
When the rough is greatly broken up, buy for what you see, and buy, if you can, pieces that have more butt on them so you can go deeper into the unseen part of the material and perhaps win more than what you paid for.

Buy some cheaper pieces to play with and learn.

Buy a parcel, several pieces so that "everything" doesn't depend on one piece.

Look at some finished stones to get a feel for what to expect in your pieces of rough.

Remember Yowah has nutbands of empty nuts all over the place, driveways are made with broken empty non-carrying nuts. Unbroken nuts by the carload can be mined and sold with no fear in the miner that there is opal in them that he is missing. You are better off with a partially broken nut with some color that you can see. However, I can vouch for the thrill of breaking open nuts that you expect are dry anyway as we all have that hope for a gambler's bonanza. Just make sure an unbroken nut, if yuou can find one, is very, very cheap. Most dealers can't make a profit in selling nuts that are unbroken, cheap. Shipping heavy ironstone overseas is expensive, and let's face it, most cutters want some opal for their money, not just experiences.

Maggoty opal is an Aussie adjective in reference to ironstone matrix opal, and means that there is a lot of clay spots and holes interwoven in the body of the stone. I find this gives texture and appeal to designer stones, but be careful that the integrity and strength of the stone does not suffer in the cutting. Maggoty matrix can be purchased cheaper, and if it causes you too many problems can always be opticoned or soaked in a hardener and then classed as a treated stone.

Look for black matrix as a black stone has more value (these will be hard to find).

Just because ironstone nut material looks dry or maggoty doesn't mean there isn't a pool of great gem opal in it, but don't pay for possible and maybes. Stick to what you see and don't pay too much for just a gamble.

Look at the rough wet and in the brightest sunlight to catch an indicator that might have been missed by the miner or the vendor. If there is a lot of opal showing in the piece, look at it dry for cracks as the nature of the mining methods can be rough on them.

Yowah rough is sold by the piece, the pound, or by the container. There is no standard. Use your eyes, your knowledge and that of the vendor, and put your money where your mouth is. Good luck and enjoy!