There is no electricity at Koroit. There is no running water either. What there is, buried in the hard ironstone of this remote patch of South West Queensland, is one of the most distinctive boulder opals on the planet, and that has been enough to draw people out here for well over a century. Koroit is not a town and never has been. It is an opal field, about 80 kilometres north-northwest of Cunnamulla, far enough from anywhere that the roads in are often the most dangerous part of the trip. People come anyway, because the stone that comes out of the ground here looks like nothing else.
Most opal is prized for a clean, uninterrupted sheet of colour. Koroit boulder opal is loved for the opposite: the way precious opal threads and webs its way through the surrounding ironstone in intricate, maze-like patterns, so that each finished stone is a kind of natural abstract painting. Geologically, this is a kernel of opal forming inside small concretions in the rock. In Queensland, boulder opal occurs within a belt of sedimentary rock roughly 300 kilometres wide, part of the Winton Formation laid down when an ancient inland sea covered much of the continent. At Koroit the opal and its dark ironstone host are inseparable, and cutters deliberately leave them married together, letting the brown stone frame the bursts of blue, green and gold.
The Koroit field was discovered in 1897 by Lawrence Rostron, the manager of nearby Tilboroo Station out of Eulo. A burst of early activity followed, with syndicates sinking shafts and chasing the colour through the first years of the new century before the work tapered off. The field did not truly come back to life until 1972, when rising demand and prices for boulder opal made the hard, remote digging worthwhile again. Mining at Koroit takes two forms: large-scale open-cut work that strips back the overburden, and the older method of underground shafts driven down to the opal-bearing levels. Both are slow, dusty and unforgiving, carried out in a place with none of the comforts of home and a long, rough drive to the nearest supplies.
Koroit lies close to the better-known opal town of Yowah, which produces a similar ironstone opal, and the two share the same harsh, beautiful country. This is deep outback: flat red and ochre ground, scattered mulga, and tracks that turn treacherous after rain, when the surface clay becomes a slick paste that can strand a vehicle for days. There is a strict warning embedded in Koroit's reputation, too: it is not to be confused with the gentle dairy town of Koroit in rural western Victoria, a green and watered place that could not be more different from its arid namesake. Out here there are no services to forget, because there were never any to begin with. You bring your own water, your own power, your own everything.
The payoff for all that hardship is a gemstone collectors travel the world to find. Koroit opal has become a signature of the Queensland fields, sought for exactly the qualities that once made boulder opal hard to sell: its irregular shapes, its dark matrix, its veins of fire running wild through stone. Each piece is unrepeatable, shaped by how the opal happened to fill the cracks and cavities of a particular nodule millions of years ago. To hold a polished Koroit stone is to hold a slice of an ancient seabed, lit from within. That such things come from a place with no power, no water and no town at all is the kind of contradiction the outback specialises in, and the reason people keep making the long, hard drive out to dig.
The Koroit opal field sits at roughly 27.59 degrees south, 145.36 degrees east, in remote South West Queensland about 80 kilometres north-northwest of Cunnamulla and close to the opal town of Yowah. From the air it shows not as a settlement but as a cluster of pale workings, open cuts and shaft mounds scattered across flat red ironstone country crossed by unsealed tracks that are notoriously treacherous when wet. There is no airstrip, power or water at the field itself; the nearest sealed runway is Cunnamulla (YCMU) to the southeast, with Quilpie (YQLP) and Charleville (YBCV) the next options for fuel and services. Expect wide-open, obstacle-free terrain and strong visibility in dry weather, with heat haze and thermals over the bare ground during the day and effectively no ground support across this empty stretch of outback.