Australian Boulder Opal Rock

Apr 2, 2020 | Opal Talk

Let’s talk rough!


Let me first state that there is no bad language contained within.

The term rough in this article refers to raw, unprocessed opal bearing rock which is mined in Western Queensland, Australia …… where once there was an inland sea, conifer forests and dinosaurs roaming around.

The countryside, now, is dry and arid. Cattle and sheep grazing properties occupy most of this area. Little country towns dot the region like Winton, Longreach, Barcaldine, Blackall and Quilpie, many of which rely on artesian bore water (deep, hot, underground water) for their water supply. Which is said to be the remnants of the inland sea. This inland sea is also to be accredited for the opal phenomenon. see how is opal formed.

The opal miners choose quite a tough lifestyle working daylight with mainly camp style accommodation and living remote. And it’s been said that there’s a lot of dirt mixed in that opal, so finding rough opal isn’t so forth coming, particularly gem grade.  All grades of the boulder opal rough are mined in this region and can vary through high gem, commercial, specimen, and potch.  Mining is a seasonal activity as temperatures in summer make it near impossible to live here let alone mine.

The main distinctive characteristic of Australian rough boulder opal is the host rock in which the opal is found in. The host rock can vary from ironstone to sandstone, as well as a composite of both and of reasonable hardness. Because the host rock is mainly a sedimentary conglomeration, the patterns, swirls and color contrasts of the rock itself is very scenic. Now introduce the opal into the mix in the form of veins running through the rock and even the rough opal looks attractive and intriguing.

When fortune favours the miner and boulder opal rough is found it is graded in to parcels. The term ‘parcel’ doesn’t infer a set volume or weight, it is a sorted group of boulder opal rocks. The value of the parcel is determined by the color within each rock, looking at color type, number, richness, intensity, pattern, opalescence – presence of piece. Setting the value on the unprocessed opal ore is arrived at through experience and of the yield type from the area.

You can buy rough in a 200 litre / 44-gal drum for a few thousand dollars, as opposed to a 2-litre sized ice-cream sized container for many 10s of thousands of dollars.

Expect to have very differing color quality.

You can’t beat the Australian Boulder Rough Opal for charismacharm and intrigue. It will entice anyone who comes upon it. There seems to be an innate attraction for many that manifests right from childhood. When we do exhibitions, it is often the child dragging the parent over to engage with the rough opal we have on display. The parent very soon reconnects with their child-self and becomes awe struck.

Now you can go and get ………. enchanted by nature’s art

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