Western opal fields
Yowah fossicking area
The Yowah Fossicking Area sits within the historical Yowah Opal field; the southernmost opal mining centre of western Queensland with well-known opal mineralisation areas such as Black Gate. Yowah is about 160km west of Cunnamulla. The Yowah Fossicking Area is popular with tourists and fossickers as it has easy access from main roads and is close to the town of Yowah which provides access to shops, fuel, a telephone, a caravan park, and a permanent bore water supply. Yowah is a small town that sees its population increase significantly during winter, when the town hosts its annual Opal Festival which celebrates the prized Yowah Nut.
Access
From Cunnamulla, head west on Adventure Way for about 85km , then turn right onto the Yowah/Toompine road and travel 48km via Alroy homestead to the Yowah–Quilpie turn-off. Continue a further 23km to Yowah; via Jandel Road and Yowah Opal Fields Road.
From Quilpie, follow Quilpie-Thargomindah Road for 113km through Toompine Turn left onto Eulo-Toompine Road towards Yowah/Eulo. Follow this road for about 56km to the Yowah turn-off, turn right and then continue the further 23km to Yowah via Jandel road and Yowah Opal Fields Road.
Map
Facilities
Camping is prohibited. There is accommodation available in the town of Yowah.
Fossicking notes
A feature of the Yowah field is the occurrence of precious opal in siliceous ironstone nodules generally referred to as Yowah Nuts. These nuts range from about 5mm to 200mm across, have a spherical or ellipsoidal shape, and show alternate concentric rings or bands of light- and dark-brown siliceous ironstone. There is sometimes a kernel of precious opal, which is the main source of the gem.
The nuts are found in layers (150–600mm in thickness) at depths up to 20m in a ferruginous sandstone, and are commonly associated with mudstone fragments or clay pellets.
The main layer is located near the contact between the sandstone and underlying mudstone/claystone, but scattered nodules, and in some cases a second band, may occur above.
The lateral continuity of the nut bands is somewhat difficult to predict owing to the irregular bedding of the strata, as well as the lack of any detailed mapping. In some shafts, the nut band was not encountered, but the sandstone at its contact with the mudstone was found to be more ferruginous and cemented by partial opalisation into a hard band, which also contained opal in the form of seams and pipes.
The eastern part of the fossicking area has always been popular with tourists as a place to speck or noodle fragments of opal or ironstone matrix from the surface or shallow depth. In this area the main nut band appears to have been exposed at the surface, so that a layer of loose rubble of broken ironstone nut fragments covers the surface to a depth of about 600mm. Spotting chips of opal or fragments of matrix while digging through this material is relatively easy with a bit of practice.
Special conditions
There are some areas excluded from the fossicking area, including several mining claims and a former mining lease area (see Map 664.6 KB)) which must not be entered.